Description. "Shell. Very small, porcellaneous, translucent, oval, very slightly broader in front; its side slopes are slightly, its front slope extremely convex, its back slope is short and flattened and very much overhung by the protuberant apex; there arc sparse and distinct riblets. The slit is short and coarse, though not large: and from it a broad round ridge trending to the right runs to the margin. Sculpture. The riblets are neither strong nor sharp; but they are distinct, rising as little round threads from the surface, and being parted by broad intervals, rather strongly pitted by the little specks of the genus; the ridge which runs down the front of the shell is the full breadth of the slit: the concentric striae are mere slight irregular lines of growth. Color clouded, porcellaneous white under the brownish caducuous epidermis. Apex very much curled in and bent down, but not spread out on the backward slope: the minute extreme tip is exserted and projects; the whorls 2£. Slit: the open part is short and narrowly oblong, and as broad in front as behind, from which point the old sear runs up the crest. Margin thin, patulous, especially behind, crenulated by the riblets. Inside porcellaneous, deeply hollowed into the apex; scored by the rib-furrows, of which the one in front is very strong, particularly near the slit, which is rather closely covered by the strong, slightly arched septum, which has a retracted edge and is unbuttressed.
In the animal the eye-peduncles are present; but no eyes are visible: the pedal papillae are very small, as is also the funnel-shaped process leading to the shell-slit. Length 4,5 mm; Width 3 mm; Height 2,5 mm. The type locality is off Halifax, Nova Scotia.
Remarks. I have not seen this species. The description and the figures are taken from Watson. Although Watson in his description states that in brychia the old scars of the fissure run up to the crest, thus seeming to indicate that it possesses an anal fasciole, the figure shows a long septum running very near the surface and closing most of the fissure, very much as in P. clathrata. For this reason I include brychia in Puncturella s.s. and not in Cranopsis where it would belong if Watson's description alone were taken into consideration.