Frond very minute, constriction very obtuse and shallow; segments in front view broadly elliptic, outer margin bordered by a few very minute, opaque tubercles or granules; end view broadly clliptic.
A small pool, near the ice-houses, on the Pipers-town road, county of Dublin.
Frond very minute; in front view about one fourth longer than broad; constriction wide, shallow, forming an obtuse angle ; isthmus wide; segments broadly elliptic, outer margin bordered by a few (5—7, often 6) very minute opaque superficial tubercles oi’ granules; side view narrower, about twice as long as broad; constriction a mere gentle depression or concavity at each side, segments forming about two thirds of a circle, outer margin, as before, bordered by a few minute, opaque tubercles; end view broadly elliptic. Sporangium unknown.
Length of frond, to breadth, to depth, of an inch.
Plate XII, fig. 11, front view; fig. 12, side view; fig. 13,...