With Plates 19 and 20, and a Text-flgure.

The following is a continuation of the work on Notoryctes typhlops, of which Part I, on the Nose and Jacobson’s Organ; Part II, on the Blood-vessels; and Part III, on the Eye, have already been published [11, 12].

It has been thought well to make the record of the anatomy of Notoryctes more complete by incorporating here a fuller account of the skin and hairs, and also of the reproductive organs and associated parts, than has previously been given.

Professor Baldwin Spencer has therefore kindly handed to me the drawings and notes he had made in connection with these structures; for this, as also for access to his stock of animals, I wish to record my indebtedness and thanks.

As stated previously in another place no embryonic material is forthcoming, so that no facts concerning the development of these parts can be given.

The skin forming the surface of the body generally, consists of two or three layers of cells, covered by a thin corneous layer (Pl. 19, figs. 3, 4, 12, e.). Over the snout and tail the epidermis becomes most highly developed forming the strong horny coverings to those parts. The skin undergoes modification, also in the region of the special “ischiotergal patch,” on the hinder part of the back, overlying the ischiotergal slip of muscle previously referred to by Dr. Stirling [10, p. 159], Professor Baldwin Spencer [8, p. 46], and Professor Wilson [13, p. 6]. The diameter of this patch varies as measured in sections, from 9 mm. to 10 mm., 9’6 mm. being an average width. It can always be seen from the exterior by its darker golden-brown colour.

The varying thickness of the skin in different parts is seen in the following table :

The thinness of the dermis in the snout is due to the absence of hairs in that part, while in the chin and general surface of the body, and especially in the ischiotergal patch, these structures are highly developed. Immediately below the level of the hair-roots in this modified region, is a thick layer of fat cells. The greater thickness of the dermis here does not end abruptly, but gradually decreases from the centre of the area till it reaches the margin, where there is a small sudden decrease in thickness, marking the boundary of the patch [cf. 8, pp. 45, 46].

The difference in thickness of the corneous layer in the modified patch, and over the general body surface, is occasioned by the compactness of this layer in the former case, and its looseness in the latter.

As in Ornithorhynchus [cf. 7 and 9] and Echidna [cf. 9] the hairs are of two kinds, large and small, arranged in bundles (Pl. 19, figs. 1 and 3) containing usually one large and a greater number of small hairs [cf. 8, pp. 45, 46]. The hairs of each bundle have a common neck and opening (figs. 2-4, c.f.o.) to the surface, where the individual follicles are absent.

The bundles are furthermore arranged in groups of three (Pl. 19, fig. 1), or sometimes four or even five, in more or less straight lines, each bundle, however, having its own follicular opening not communicating with that of the other bundles in the group (see Pl. 19, fig. 2), so that in transverse sections near the surface, the group arrangement is often lost.

The arrangement at deeper levels is shown in Pl. 19, fig. 1, where we have a typical group of three bundles from the skin of the back. The number of small hairs in each bundle varies from nine to twenty, the most numerous examples showing from eleven to nineteen. Occasionally the large hair seems to be absent. As will be seen, there are in the group figured—

Successionsl hairs are only occasionally seen.

Each bundle is separated from those around it by a deeply staining, more or less compacted fibrous tissue. In the ischiotergal patch, and on the chin and side of the head, the bundles are more closely packed together than on the shoulder, thigh, and body generally.

The large hair grows in various positions in the bundles, generally posteriorly, but by no means always so.

The muscles connected with the hairs are as usual unstriated, both in the ischiotergal patch and elsewhere.

In the modified patch, around the cloacal opening and on the head, the sebaceous gland mass often almost entirely surrounds the bundle, lying both between the latter and its muscles, and between this bundle and its fellow. The glands in this modified area, and those around the cloacal opening are also very long, extending well down towards the hairroots, and even below them (Pl 19, fig. 4), but on the side of the head and under the chin, though the glands often extend round the bundles, they are very much shorter than in the ischiotergal patch specially.

On the shoulder and thigh, as well as the general body surface the gland mass is very much smaller and shorter (see Pl. 19, fig. 4). The main duct of the gland is found most often just behind the large hair of a bundle, and should the large hairs of the three bundles in a group vary in size, as often happens, the largest hair and gland duct is generally to be found in connection with the most central bundle.

The greatly marked glandular development of the ischiotergal region, and the peculiar structure of the ends of the hairs, as described below, no doubt account for the usually matted character of the hair-covering over this area.

The ordinary hairs, both large and small, forming the fine silky golden covering of Notaryctes vary considerably in diameter below the epidermis as seen iu the following table:

The average size for the shaft enclosed in the skin is for the large hair ·040 mm., and for the small hair ·007 mm.

In depth below the surface of the epidermis we find variations according to the region; thus over the body generally a typical large hair may extend for ·49 mm. below the stratum corneum, while in the “ischiotergal “patch it is commonly 1·66 mm. in depth, though it may be more.

Such difference in length may easily be found only 9 or 10 mm. apart. The hail’ roots are also very long in the head region, but not so much so as in the modified patch.

In structure [cf. 8, pp. 45, 46] the large hairs are not unlike, though much smaller than, those of the Ornithorhynchus [cf. 7 and 9], They have a rapidly tapering smooth tip (Pl. 19, figs. 5 and 6). This is succeeded by a wide flattened part, which in a typical hair at a distance of 1 mm., from the tip is ·09 mm. wide. From this point downwards we find a diminution in size till at its exit from the follicle it is round, and ·03 mm. in diameter. The tip is solid, but in the wider shield and long smooth shaft, the medulla is much vacuolated; the air cavities become regularly arranged, so as to give the ladder-like appearance at about 2 mm. below the extreme point. There is no pigment in the older hairs, though in the successional large hairs there is pigment in the centre of the flattened shield.

In the ischiotergal patch, however, these large hairs are much pigmented right to the free end, causing the darker colour of this area. The tip, moreover, instead of being smooth and pointed as elsewhere, is deeply split (Pl. 19, figs. 9 and 10), giving rise to a somewhat brush-like appearance at the end of each hair. These are frequently -1 mm. in width just below the division.

The small hairs are imbricated all over (Pl. 19, fig. 7), and taper gradually from base to tip over the general surface, but in the ischiotergal region (Pl. 19, fig. 8) they are irregularly waved near the tip, somewhat resembling a badly made spear.

The roots of both large and small hairs are situated at about the same level in the dermis. In minute structure the hair sheaths, as well as the hail’s, are normal.

The long straight hairs found around the cloacal opening in both male and female are in distinction to those of the rest of the body surface, not disposed in bundles, but are isolated. In diameter they average ·047 mm. to ·05 mm.

When examining the epidermis over the region of the rudimentary eye, I found curious modified groups of epidermic cells with a more or less definite arrangement; and, on further investigation, they are met with over most of the head region, over the modified ischiotergal patch, and in the pouch region. The epidermis over the head region, i. e. behind the snout, consists of at most three layers of cells, except at special points (Pl. 19, fig. 12). Here the epidermis is much thicker (Pl. 19, fig. 12, s. o.), having four or five layers of cells, causing the Malpighian layer to become depressed into the dermis, and the stratum corneum to become slightly raised. Sometimes the whole structure resembles a raised platform, often like a much-truncated cone in outline. In horizontal diameter the top of the modified area varies from ·11 mm. to ·15 mm.; while in vertical depth, excluding the corneous layer, it is ·04 mm. to ·06 mm. The whole area of the Malpighian layer involved may have a diameter of 2 mm. The slightly larger examples were found in the ischiotergal patch, though these structures are much more conspicuous in the region of the head and neck, since there, as previously stated, the whole normal Malpighian layer may be only -01 mm. thick. These structures are normally separated by a space of 2·5 mm.

The loose outer part of the corneous layer, which so readily becomes detached elsewhere, tends to adhere more firmly to the underlying part over these areas. The cells of the Malpighian layer are much elongated and thinner, and, in addition to sloping upwards and inwards, they are much crowded horizontally.

A tendency to become arranged around a central core is to be noted in some cases. Their nuclei are also much elongated and larger. In the modified “ischiotergal” patch the whole epidermis is, as previously stated, much thickened, but these cutaneous structures are equally, if not more commonly, developed there than in the skin of the head region. Over the shoulder and thigh regions, as over most of the body, these cutaneous organs do not appear to be present. The structure is often pierced by a group of hairs, or it may be flanked by such a group, while, on the other hand, they would seem often to exist without any relation to hairgroups.

Beneath the modified epidermic areas, there can generally be seen a group of more numerous connective tissue cells, not unlike those found in a developing hair-papilla. Sometimes there is a group of about a dozen oval cells staining less deeply than the cells above, and with two or three welldefined nucleoli, I have not been able to detect either nerve or blood supply to these structures, though in a few cases the oval cells appeared to give off processes towards the Malpighian layer, the cells of which immediately above are very pointed, and almost spindle shaped, penetrating the second layer of more cubical cells.

The general appearance of these structures is that of a taste bud with the stratum corneum continuous over it, and not unlike a developing cutaneous sense organ of Triton.

Of the sensory function of these structures I can therefore offer no conclusive evidence, but it is reasonable to suppose that in the absence of the sense of sight and pari passu with the apparently increased olfactory function, there might exist some special organ or organs of tactile sense in Nbtoryctes, as in some other forms. It is at least possible that such may be the function of these special cutaneous structures. They cannot be early stages of developing hairs from the fact that they are present in the fully-grown animal alongside well-developed bundles of hairs and often pierced by such bundles.

Further they are quite different in structure and size from those very early stages of a developing hair which at first sight they slightly resemble.

So that, although direct proof of such nervous character is wanting, one is led to consider it probable that they are some form of tactile sense-organ, which must be of special use to such a burrowing, sightless animal as Notoryctes.

My observations confirm those of Dr. Stirling as to the position, appearance, structure and relations of the testes, epididymis, vasa deferentia, and their associated bloodvessels; also as to the absence of any external scrotum. The following additional points are worthy of note.

Around the base of the thick muscular-walled bladder (Pl. 20, figs. 13—16, blr.), and extending over the origin and anterior part of the urethra, is a well-marked glandulai’ part evidently prostatic in character, and enclosed by a stronglydeveloped circular muscle coat. Within each of the large muscular bulbs attached to the root of the penis is a welldeveloped corpus cavernosum with thick fibrous walls. These corpora cavernosa leave the muscular masses and approach each other posteriorly in the mid-ventral line beneath the urethra, forming the “cylindrical body” described by Dr. Stirling [10, p. 182], though, owing to the absence of sections, he was not able to determine the presence of the corpora cavernosa. At the plane of coalescence of the median walls of the corpora cavernosa (Pl. 19, fig. 18, c.c.), the corpus spongiosum (Pl. 19, fig. 18, c.s.) appears ventral to them again, and with them, extends posteriorly into the penis. This organ lies in a preputial sac ventral to the rectum, and on its dorsal side some distance from the tip (which contains only a blood-vessel) the urethra opens by a long slit-like opening.

In this region the rectum loses its typical glandular character, the cloaca being lined by a very thick stratified epithelium (· 095 mm. in thickness), which has a thick, corneous layer. When seen in section, it is very conspicuous when contrasted with the epidermis which consists of two or three layers only (· 028 mm. thick) in this region. The lining epithelium of the cloaca is also very much folded, and rests upon a thick layer of submucous connective tissue. Extending along the length of the cloaca, to neai’ its external opening there are as in Perameles [4, p. 57] a number of much-coiled branching diffuse tubular glands lying amongst the muscle bundles of the cloacal wall, and in the connective-tissue surrounding it, especially dorsally and laterally. These gland tubes, which maybe found also to a less extent around the rectal wall (Pl. 19, fig. 18, g. t.), have very thin walls, composed of cells, which are small and distinctly nonglandular in appearance, and yet the lumen always contains secretion.

Their ducts, in number about thirty, open along the whole length of the cloaca, dorsally, ventrally, and laterally, though most numerous dorsally.

On either side of the anterior- half of the cloaca, or even more anteriorly still, lies an “anal gland” (Pl. 19, fig. 18, a. gl.) similar to those of some other Marsupials, a single duct from each [contrast Dr. Stirling, 10, Pl. 9, fig. 5] running backwards in the adipose tissue outside the musclelayers of this part to enter the cloaca laterally, close to its hinder end [cf. Perameles, 4, p. 57]. These are readily distinguishable in sections from the diffuse gland ducts by their size and structure, while the other two pairs of ductlike structures described and figured by Dr. Stirling are seen to be simply fibrous bands anchoring the gland in position. This anal gland is most curious in structure, as indicated by Professor Hill in Perameles. It consists in Notoryctes of an almost spherical hollow ball, 2’4 mm. in external diameter, with a fibrous capsule, from which processes pass inwards, just comparable to the trabeculae of a lymphatic gland, and forming a more or less complete network. Unlike a lymphatic gland, however, the centre of the ball is hollow (1’4 mm. in diameter), and the whole gland appears to be surrounded by striated muscle-fibres [cf. 1, pp. 157, 161, and contrast 4, p. 57]. Between the trabeculae the alveoli are filled with long oval cells, those nearest the capsule containing protoplasm with deeply-staining nuclei. As they pass inwards towards the central cavity, however, these cells lose their nuclei and become disintegrated, so that the ball contains a greater or less quantity of broken-down material, which is passed to the exterior by the duct and cloaca.

In the region of the cloacal opening are numerous solitary large hairs. Associated with the bundles of hairs are also very greatly developed sebaceous glands, which may extend below the hair-roots, but do not occur unless in connection with the hairs. They are only found around the hinder end of the cloaca, and always lie outside, and generally separated from, the muscular wall of the cloaca.

We have in Notoryctes, therefore, representatives of three of the types of glands, described by Professor Disselhorst and others as found in connection with the reproductive organs in Marsupials, viz. in Cuscus orientalis, Sminthopsis crassicaudata, Macropus robustus, etc. [cf. 1, pp. 154—163], viz.:

  1. The tubular glands lined by a single layer of cylindrical epithelial cells.

  2. The rectal or anal gland with a duct unbranched, as in Sminthopsis, and Cuscus, and Antechinomys, leading into the cloaca.

  3. Hair glands—large complicated sebaceous glands which do not here, however, lose their close relationship to the hair-follicles, as they do in Sminthopsis, etc., where they come into connection with the tubular and the rectal glands, and lie amongst the muscles of the cloacal wall [1, p. 161, fig. 159]. Nor is there here any special development of muscles around these enlarged sebaceous glands, as described by V. Den Broek for Cuscus orientalis [1, p. 161].

As to the morphology of the rectal or anal gland which V. Den Broek has considered to be a highly developed modified sebaceous gland [1, p. 163], this seems to me most probable from the somewhat similar general internal arrangement of some of the larger groups of sebaceous glands found around the cloacal opening of Notoryctes—though these have not in this form a striated muscular investment such as surrounds the anal gland; and also from the fact that the secretion of both is necrobiotic involving the death of the cells [2, p. 29]. Of the fourth type of gland described by V. Den Broek [1, p. 163] there is no special representative in Notoryctes.

It is of especial interest to note the relations and comparative morphology of these organs in all Marsupials since Professor Hill’s valuable work on those in Perameles.

Hence to the admittedly incomplete description and somewhat erroneous figure given by Dr. Stirling, and the brief comments of Professor Spencer, further details are here added, together with the necessary figures. The whole of these organs have been examined by means of several sets of serial sections, and in addition by dissection.

The various relations herein described may be better understood by reference to the accompanying text-figure, in which the parts are represented as seen from the ventral surface, and to scale as far as is possible for serial sections.

In Notoryctes, as in some other marsupials, there are in addition to the ovaries, oviducts, uteri, and vaginae proper, two lateral vaginal canals, with vaginal caeca, and a median vaginal apparatus. The bodies of the uteri (text-figure ut. b.) are much twisted, and their internal surface is folded and glandular. They lie ventrally to the rectum with their mesial surfaces almost touching in the middle line anteriorly, while posteriorly they are separated by the anterior end of the bladder (ant. b. of blr.). Their posterior ends approach each other almost transversely to the length of the animal, to enter the uterine necks (ut. n.), which are much smaller and lie close together ventrally to the rectum, and dorsally to the fundus of the bladder (see Pl. 20, fig. 13, ut. n.). The convoluted bodies of the uteri may in some extend for a short distance alongside the bladder, and ventral to the necks of the uteri, the long axis being parallel to that of the animal. In some of these respects Notoryctes resembles Myrmecobius fasciatus [5, p. 520] rather than Perameles obesula. The uterine necks, the internal surfaces of which are much folded, pass backwards often in contact with each other, and embedded in connective tissue, to open into the vaginas on a small papilla (see text-figure, and Pl. 20, fig. 14, ut. n.) as in Tarsipes [5, p. 523] and Acrobates [5, p. 525].

Passing backwards from these openings are two large median vaginae (text-figure, and Pl. 20, figs. 14, 15, med. v. c.), separated for some distance back by a septum which is’ absent, however, at the extreme posterior end, leaving a small opening, apparently a natural one, by which the two median vaginal canals may communicate with one another. In the possession of this communication Notoryctes is quite unlike the young Perameles [4, p. 54], young Dasyurus [6, p. 371], Myrmecobius [5, p. 526], or the young Trichosurus [5, p. 528], etc., and more like Petaurus [5, p. 526] or Acrobates [5, p. 525].

It is, however, normal in the termination of the median vaginae “blindly in the connective tissue between the posterior ends of the lateral vaginal canals, and in comparatively close proximity to the urogenital sinus.” The anterior limb of each vagina (text-figure, and Pl. 20, fig. 14, a. v. c.) passes forwards from the opening of the uterine neck. It is very short, but wider and thinner walled than either the neck of the uterus oi1 the lateral vagina. It lies laterally to the uterine neck of its own side, and very soon opens into a fairsized expansion (text-figure, and Pl. 20, fig. 13, vag. c.) corresponding to the much larger vaginal caecum on either side in Perameles, its anterior border in Notoryctes being situated at about half the length of the uterine necks. In Notoryctes, moreover, in contradistinction to Perameles, the vaginal caeca being smaller, never lose their close relationship to the uterine necks. Each lateral vagina (text-figure, and Pl. 20, figs. 14—16, I. v. c.) runs back as a small, thick-walled, straight, or slightly-curved tube laterally to the anterior limb of the vagina and the median vaginal canal, and separated from the latter by the ureter (text-figure, and Pl. 20, figs. 14—16, ur.), which comes here to lie more ventrally than in its anterior part. Thus the whole of these tubes in this region, i. e. the median vaginal canals, the ureters, and the lateral vaginas, lie in the same horizontal line ventral to the rectum and dorsal to the bladder (Pl. 20, figs. 14 and 15).

As in other allied forms, there is here a urogenital strand which contains anteriorly the necks of the uteri, the anterior limbs of the vaginas, the vaginal caeca, and the lateral vaginas, and more posteriorly the median vaginal canals, the ureters, and the lateral vaginae, with the hinder half of the bladder and the whole length of the urethra. Indeed, so closely bound together are these parts that a true conception of their relations cannot be obtained by dissection. Notoryctes then, in this respect, also may be compared with such forms as Perameles, Tarsipes, and Acrobates, and contrasted with the free coiled lateral vaginae of Myrmecobius.

Posteriorly to the median vaginals, and occupying the short space between it and the anterior extremity of the long, narrow, urogenital sinus, there lies a mass of dense deeplystaining connective tissue (text-figure, and Pl. 20, fig. 16, s.c.t.) exactly similar in appearance and position to that in Perameles [4, p. 54, 55], and other’ forms, through which in Perameles birth takes place. Careful examination of this part in Notoryctes has failed to show any indication of a split such as occurs in other forms, such as Perameles, Tarsipes, Macropus, Trichosurus, and Dasyurus, but it is open to question whether this means that the animals examined had not borne any young, as might possibly be indicated by the absence of spermatozoa and their accompanying secretion in the ducts, and by the general appearance of the parts, or, that parturition having taken place similarly to Perameles, the epithelium has been completely renewed, as in Perameles and Dasyurus, and even the split in the connective tissue has been quite closed, as in Dasyurus also.

Certainly, unless these animals were virgins, there is here no permanent pseudo-vaginal passage [cf. Acrobates], and even were they not so, the connection between the two median vaginal canals, shows no trace of any such forced opening as occurs at birth in older forms of Perameles and Acrobates, so that we may infer that a median vaginal connection is normally present, as in Petaurus.

At the same time, I should judge that birth takes place, as in Perameles, through a pseudo-vaginal cleft in the connective tissue, and not through the lateral vaginal canals.

We may notice particularly in concluding this part—

(1) The sharply marked distinction between the uterine and vaginal parts of the ducts.

(2) The large size of the median vaginal canals in comparison with those of other forms and with its own vaginal caecum, and the intercommunication of the two median vaginal canals.

(3) The presence of the urogenital strand which encloses the anterior vaginal canals as well as the other ducts, as in Perameles, Peragale, etc., and that of the dense connective tissue anterior to the long urogenital sinus.

Notoryctes then, like Perameles, seems to be more primitive in type, as far as its female reproductive organs can show.

Pouch.

As previously described by Professor Spencer [8, p. 49] the pouch is present in both male and female forms, as in some other Marsupials. In the male it is but slightly, though unmistakably, developed, while in the female, it is naturally much larger. My observations confirm the statements hitherto published [8 and 10] as to the position and relations of the pouch and mammae, etc. The general appearance is shown in Pl. 19, fig. 17, herewith.

The epidermis of this region is similar to that of the rest of the body, but has, here and there, some of the special “sense organs” described in Part IV. The dermis is dense and deeply staining around the pouch area, least so on the roof of the pouch cavity. The sphincter marsupii is present, and lies deep down in the very thick layer of adipose tissue in the walls of the pouch. This tissue also contains numerous bundles of non-striated fibres, mostly transverse, with others longitudinal to the body. The dermis has a very abundant blood-supply.

The groups of hairs are less closely packed in this area, especially on the roof of the pouch cavity, and usually consist of three bundles each. The hairs are chiefly of three average sizes—the largest yellow-brown in colour · 018 mm. thick, the smaller ones, which are colourless and much imbricated, being · 006 mm. to · 009 in diameter.

The sebaceous glands are very well developed, especially around the circumference of the mammas. Beneath the mammae the dermis extends even more deeply than elsewhere, and contains numerous mucous ducts. The mammary ducts, three to four in number, open close together on the apex of each mamma, and have, in a marked degree, the characters of sudoriparous glands, as opposed to sebaceous glands; so that, as in Monotremes [2, p. 40] the mammary glands and sweat glands are apparently homologous in Notoryctes also.

Disselhorst
. —
‘LehrbuchderVergleichendenMikroskopischen Anatomic der Wirbelthiere,’ Vierter Teil
, pp.
154
163
.
Eggeling
. —“
Ueberdie Hautdriisen der Monotremen
,”
‘Anat. Anzeiger,* Bd
.
xviii
,
1900
, pp.
29
42
.
Hill
. —“
Placentation of Perameles
,”
‘Quart. Journ. Mic. Sei.,’
vol.
40
, N.S., pp.
385
et seq.
Hill
. —“
Contributions to the Morphology and Development of the Eemale Urogenital Organs in the Marsupialia “I. Perameles
,”
‘Proc. Linn. Soc. N.S.W.,’
1899
.
Hill
. —“
II. Myrmecobius fasciatus
,”
‘Proc. Linn. Soc. N.S.W.,’
1900
.
Hill
. “
III. Tarsipes rostratus
,”
‘Proc. Linn. Soc. N.S.W.,’
1900
.
Hill
.
“IV. Acrobates pygmteus,7
’Proc. Linn. Soc. N.S.W.,’ Petaurus breviceps,”
5
1900
.
Hill
. “
V. Trichosurus vulpecula
,”
‘Proc. Linn. Soc. N.S.W.,’
1900
.
Hill
. —“
Fætal Membranes, Placentation, and Parturition of Native Cat (Dasyurus viverriuus)
,”
‘Anat. Anzeiger,’
Bd.
xviii
,
1900
.
Poulton
. —“
Structure of the Bill and Hairs of Ornithorhynchus paradoxus
,”
‘Quart. Journ. Mic. Sci.,’
vol.
36
, p.
143
.
Spencer
. —
‘Report on the Work of the Horn Scientific Expedition to Central Australia
,
1896
,’ “
Mammalia
,” pp.
45
et seq.
Spencer and Sweet
. —“
The Structure and Development of the Hairs of Monotremes and Marsupials
,”
‘Quart. Journ. Mic. Sci.,’
vol.
41
, pp.
549
et seq.
Stirling
. —“
Description of a New Genus and Species of Marsupialia, and Further Notes on the Habits and Anatomy of Notoryctes typhlops
,”
‘Trans. Roy. Soc. S. Aus.,’
1891
, pp.
154
et seq., and pp. 283 et seq.
Sweet
. —“
Contributions to our Knowledge of the Anatomy of Notoryctes typhlops
,”
Parts I and II, ‘Proc. Roy. Soc. Vic.,’
vol.
xvii
, N.S.,
1904
.
Sweet
.
—Part III, ‘Quart. Journ. Mic. Sci.,’
vol.
50
,
1906
.
Wilson
. —“
On the Myology of Notoryctes typhlops
,”
‘Trans. Roy. Soc. S. Aus.,’
1894
.

Illustrating Miss Georgina Sweet’s paper on “The Skin, Hair, and Reproductive Organs of Notoryctes.”

Reference Letters.

a. Artery, a.gl. Anal gland, a.t. Adipose tissue, a.v.c. Anterior vaginal canal. Hr. Bladder, c.c. Corpora cavernosa, c.f.o. Common follicular opening, c.s. Corpus spongiosum, cl.o. Cioacal opening, d. Dermis. e. Epidermis, g.t. Gland tubes, l.h. Large hair, l.v.c. Lateral vaginal canal, m. Muscles of hair, m°d.v.c. Median vaginal canal, r. Rectum. r.s. Root sheath of single hair, s.e.t. Dense connective tissue, s.h. Small hair. s.g. Sebaceous gland, s.g.d. Sebaceous gland duct. s.o. Sense organ. ur. Ureter, ura. Urethra, ur.gs. Urogenital sinus, ut.b. Body of the uterus, ut.n. Neck of the uterus. t>. Vein, vag.c. Vaginal crecum.

(All figures except Fig. 17 were drawn by the aid of the camera lucida. For Figures 1—11 and 17 I am indebted to Professor Spencer.)

PLATE 19, Figs. 1—12 and 17—18; PLATE 20, Figs. 13—16.

FIG. 1.—Horizontal section through the skin of the back, across a typical group of three bundles of hairs, showing large (Z.A) and small hairs (s.A.), sebaceous gland (s.g.), and duct of same (s.g.d.). Zeiss C, oc. 2.

FIG. 2.—Portion of stratum corneum, showing two bundles of hairs, each emerging from common follicle (c,f.o), and showing distinct root sheaths (r.s.) below. Zeiss C, oc. 2.

FIG. 3.—Longitudinal vertical section through two bundles of hairs in ischiotergal region, showing slightly thickened epidermis (e), large (l.h.) and small hairs (s.A.), with separate roots and sheaths below (r.s.), and common follicular opening (c.f.o.) above. Also gland (s.g.) and muscles (m.). Zeiss C, oc. 1.

FIG. 4.—Small bundle of hairs from the side of the ischiotergal patch, showing greatly lengthened sebaceous gland, and also diminishing length of base of hairs. Zeiss C, oc. 1.

FIG. 5.—Shows length and shape of pointed large hairs found Over general surface of body, with root attached. Zeiss A*, oc. 4.

FIG. 6.—Same hair as in Fig. 5, under higher magnification, showing solid tip and broad shield. Zeiss C, oc. 2.

FIG. 7.—Small hair from general body surface. Zeiss C, oc. 2.

FIG. 8.—Small hair from ischiotergal patch, showing irregular surface. Zeiss C, oc. 2.

FIG. 9.—Large hair from ischiotergal region, showing outline and length. Zeiss A*, oc. 2.

FIGS. 10 and 11.—Two large hairs from ischiotergal patch, showing the brush-like, deeply cleft extremity in contrast to the pointed tip of Fig. 6. Zeiss C, oc. 2.

FIG. 12.—Section through epidermis of side of head, showing “sense organ “(s.o.), with bundle of hairs cut transversely. Zeiss C, oC. 4.

FIGS. 13—16.—Transverse sections from a complete series taken through the female urogenital ducts, their position being indicated by section lines in Text-figure (page 337). All drawn under Zeiss A*, oc. 4.

Fig. 13.—Section No. 27 through the bladder (blr.), vaginal caeca (vag.c.), necks of the uteri (ut.n.), ureters (ar.), and rectum (r.). (Contrast Hill, 4, fig. 3.)

Fig. 14.—Section No. 19 cut obliquely, showing on one side the opening of the uterine neck (ul.u.) into the anterior vaginal canal (med.v.c.) to form the median vaginal canal (med.v.c.), while on the other side the section is slightly anterior to this opening. (Cf. Hill, 4, figs. 5 and 6.)

Fig. 15.—Section No. 14 cut through septum between the two median vaginal canals (med.v.c.’) just anterior to their fusion, showing ureters (ar.) in same horizontal plane as lateral (l.v.c.) and median (nied.v.c.) vaginal canals. (Cf. Hill, 4, fig. 7.)

Fig. 16.—Section No. 10 taken through dense connective tissue (s-c.l.) connecting the walls of the median vaginal canals with the wall of the urogenital sinus, showing ureters (ar.) passing ventrally to open into the base of the bladder (blr.) close to the opening from it of the urethra. (Cf. Hill, 4, figs. 11,12.)

FIG. 17.—View of pouch cut open ventrally, showing position of the two mammte, and the relation of the pouch to the cloacal opening (cl.o.). × 2.

FIG. 18.—Section through rectum of male, showing anal glands (a.gl.), urethra, corpora cavernosa, corpus spongiosum, and gland tubes in rectal wall. Zeiss A*, oc. 2.

TEXT-FIGURE.