A. E. Verrill— Mollusca of the New England Coast. 221 
Porcupine and Valorous Expeditions, and in the Bay of Biscay by 
the Travailleur Expeditions. It has occurred at depths ranging from 
652 to 1450 fathoms. 
LAMELLIBRANCHIATA. 
Thracia nitida Verrill, sp. nov. 
PLATE XXXII, FIGURE 22. 
Shell thin, tumid, broad-ovate, gaping considerably posteriorly and 
slightly anteriorly. Umbos prominent, situated in advance of the 
middle, with the beaks strongly incurved and turned forward, leav- 
ing a broad, depressed, cordate lunular area, which is not defined by 
any definite boundary. The posterior dorsal margin descends 
slightly ; the posterior margin is slightly prolonged and bluntly 
rounded ; the ventral margin is broadly curved, becoming nearly 
straight in the middle; the anterior margin is obliquely rounded. 
The surface is nearly smooth, shining, and iridescent, marked with 
inconspicuous lines of growth, and covered with very minute, regu- 
larly scattered granule-like elevations, each of which bears a minute 
hair-like process, when not rubbed ; towards the posterior end these 
are more numerous and conspicuous, and are arranged in regular deli- 
cate radiating lines, but over the greater part of the shell they are 
scarcely visible to the naked eye. Epidermis very thin, greenish 
yellow. Hinge-margin slender, somewhat thickened along the liga- 
mental groove, and with a slight notch anteriorly for the reception 
of the minute cartilage. No ossicle was detected in the alcoholic 
specimen. Pallial and muscular impressions faint. 
Length, 21™™ ; height, 18"; thickness, 14™™. 
The animal has a circle of sixteen large, tapered, acute tentacles 
around the common base of the siphons, which are brown in alcohol. 
The efferent tube is somewhat prolonged in the contracted specimen, 
but the other is entirely withdrawn. 
Station 2097, off Chesapeake Bay, in 1917 fathoms (No. 35,267). 
Poromya sublevis Verrill, sp. nov. 
PLATE XXXII, FIGURE 21. 
Shell rather large for the genus, short, high, tumid, with prominent 
umbos and large beaks, which are curved inward and forward. The 
length of the shell is considerably less than the height from the beak to 
the ventral margin. Anteriorly the lunular region is large and some- 
