ABSTRACT
In the summer of 1891, during a stay at the village of Goring-on-Thames, I was on the look-out for Criodrilus, which hitherto has not been found in England. I looked carefully amongst the roots of waterweeds, and in the mud in which these were growing, and ultimately I believed I was successful, for I found a few worms, some three or four inches in length, agreeing closely, so far as regarded external character, with C. lacuum, with the exception that the male pore, which is very conspicuous in the latter worm, was not evident. But on further examination the worms were found to present several internal characters which did not harmonise with those of Criodrilus. However, the worms had passed the period of their sexual maturity, so that the generative system was in a degenerate condition, and I was unable to trace the sperm-ducts to a pore. I had therefore to wait till the following summer, when I paid several flying visits to Goring, with finally good results, for I found more of the worms, and this time sexually mature. The genital organs conclusively showed that a new genus was in my hands, belonging not to the family Lumbricidse, but to the Rhinodrilidse (mihi).
Oerley, “Morph.and Biol.Observations on Criodrilus,” ‘Quart. Journ. Mier. Sei.,’ xxvii, p. 537.
During August and September of ibis year, 1892, I have frequently found the cocoons in quantities in the neighbourhood of Oxford, both in the Thames, in the Cherwell, and amongst the roots not only of Sparganium, but also of Sagittaria sagittifolia and other water plants; I have, however, not come across the worm this year.
The accompanying figures, 1, 2, 3, are lithographed from coloured sketches, and some of the points which showed well in them are now indistinct.
‘System und Morphol. d. Oligochæten.’
“Sul Criodrilus lacuum,” ‘Mem. d. Reale Acad. d. Sc.,’ Torino, 37.
‘Zeit. f. wiss. Zool.,’ 46.
‘Proc. Zool. Soc.,’ 1892.
But see Garman on “Diplocardia,” in ‘Bull. Illinois State Lab. of Nat. Hist.,’ iii, pl. i.
Benham, “The Nephridia of Lumbricus,” ‘Quart. Journ. Mier. Sei.,’ vol. xxxii.
F. E. Beddard, ‘Quart. Journ. Mier. Sei.,’ vol. xxxii, Pl. XXXIX, figs. 14 and 16.
Vejdovsky, in his “Entwickelungsgeschicbte,” finds that the polar bodies in Rhynchelmis are formed in the ovisac, while in Lumbricns and Allolobophora they are not formed till the ova are laid in the cocoon.
“On Megascolex coeruleus,” ‘Quart. Journ. Mier. Sei.,’ vol. xxxii,
For references to descriptions of the genera here named, see my “Attempt to Classify Earthworms,” ‘Quart. Journ. Mier. Sci.,’ vol. xxxi.
Benham, ‘Proc. Zool. Soc.,’ 1892.
‘Notes from the Leyden Museum,* xiii, p. 77.
Perrier, ‘Nouv. Arch. d. Muséum,’ 1872.
Kynotus, Michaelsen, ‘Jalirb. d. Hamburg, wiss. Anstalt.,’ ix, 1891; and ‘Arch. f. Naturgesch.,’ 1891; Rosa, ‘Boll. Mus. Zool. Torino,’ vii, 1892. Tykonus, ‘Arch. f. Naturg.,’ 1892.
‘Annal. Mus. Cir. d. Stor. Nat.,’ Genova, 1890.
‘Zool. Anzeig.,’ 1891.
Oneor two species of Allolobophora are stated to be deprived of their spermathecæ; I am not aware at what period of life these species were examined. Allurus tetraedrus is usually stated to he deprived of them. J can confirm Vejdovsky in stating their existence. I have found three pairs opening dorsally of the lateral setæ.
