560 
A. E. Verrill — Catalogue of Marine Mollusca. 
tenor end short, narrowed, and tapered to an obtuse point. The 
beak is subcentral, but a little nearer the anterior end, prominent, 
inflated, strongly curved inward and forward. Dorsal margin ab- 
ruptly incurved opposite the beaks and decidedly expanded and ex- 
curved in front of them, so as to rise nearly to a level with the 
umbos ; internally, opposite the tips of the beaks, there is a smooth 
swelling, within the margin. Hinge-margin thin, toothless, but with 
an internal scar behind the beaks, where the ligament was attached. 
Sculpture numerous, very delicate, slightly raised lines, which radiate 
from the beaks over the whole surface; they are separated by much 
wider interspaces, which are smooth and iridescent, and not at all 
excavated. Length, 4\5 mm ; height (beak to ventral margin), 4 mm . 
One perfect specimen, station 892, 487 fathoms, associated with L. 
abyssicola. 
I have had no opportunity to examine the fossil shell which was 
the type of JPecchiolia, and therefore, in view of the differences of 
opinion among European authors, am very uncertain whether it is 
congeneric with the two preceding species. If not, then they should 
both be referred to Lyonsiella M. Sars. Jeffreys adopts Pecchiolia 
for this group, to which he also unites Verticordia. 
V erticordia caelata Verrill, sp. nov. 
Shell small, pearly within, rounded-oblong, with the beaks acute, 
prominent, and strongly curved forward. Eleven strong, sharply 
elevated, radiating ribs, separated by wider, deep, concave furrows, 
cover rather more than the anterior half of the shell ; the most pos- 
terior of these ribs are lower and wider apart ; these are followed by 
a posterior-lateral area, without ribs, but covered with fine granules, 
beneath which the surface is finely, radially striated ; close to the 
extreme posterior margin there are two small ribs. The whole sur- 
face between the ribs was probably finely granulated. The ribs pro- 
ject, as denticles, beyond the edge of the shell. The anterior border 
of the shell is a little prominent and convexly rounded, more broadly 
rounded ventrally ; the posterior-ventral margin is subtruncated, 
with an angle where it joins the rounded posterior-dorsal margin ; 
anterior-dorsal margin, in front of the beak, strongly indented. 
Right valve with a large, rounded, prominent, blunt tooth, just be- 
low the beak ; in front of this, a deep, V-shaped notch or sinus, 
formed by a sharp inbending of the hinge-margin, which is thick- 
ened and forms a triangular tooth-like projection within. Behind 
