222 A. E. Verrill — Molhisca of the New Enf/kmcl Coast. 



what excavated, rather indistinctly defined by feeble undulations. 

 The anterior end is short, very obtusely rounded or subtruncate ; the 

 ventral margin is broadly rounded, slightly obliquely produced a 

 little behind the middle, forming there a scarcely distinct, rounded 

 angle, from which a posterior, ill defined, rounded ridge runs up to 

 the beak ; posterior end very obtusely rounded and somewhat 

 oblique ; posterior dorsal margin descending rapidly from the beak 

 and slightly convex. Surface nearly smooth to the naked eye and 

 covered with a very thin, pale yellowish epidermis ; under a lens the 

 whole surface, except on the umbos, is covered with very slight, 

 rather distinct radiating lines of very minute pointed granules, which 

 are pretty evenly spaced along the lines, rather distantly on the 

 middle area of the shell, but becoming much more numerous toward 

 the posterior end, where they are connected by distinct but very fine 

 raised lines, which appear to be chiefly epidermal ; one line, more 

 distinct and more elevated than the rest, runs from behind the beak 

 to the upper part of the posterior margin, defining a narrow posterior 

 dorsal area. The minute granules scattered over the surface appear 

 to be chiefly due to the epidermis, but where the surface is somewhat 

 rubbed they still appear as minute specks, which become very fine 

 and irregularly scattered on the umbos ; where most perfect, each 

 grantile is surmounted by a minute sharp process of the epidermis. 

 The margin is sharp aud plain, with a thickened interior ridge a 

 short distance within the edge. The hinge consists of a large, stout, 

 obtuse tooth, just below the beak, which projects considerably in- 

 ward and is divided at the sunmiit into three low, romuled lobes or 

 cusps, of which the most interior is the largest and most prominent, 

 while the outermost is confluent with the lunular margin ; a support- 

 ing ridge runs fnmi the inner margin of the tooth both forward and 

 backward to the margins ; [)osterior]y, between this ridge and the 

 margin, there is a very narrow and long, curved ligamental groove, 

 running forward and terminating just under the beak above the 

 center of the large tooth ; a small, divergent, somewhat raised ridge- 

 like process, grooved on top, intervenes between the anterior part of 

 the ligamental furrow and the ))rincipal tooth. The inner surface of 

 the shell is opaque white, and marked with slight irregular lines and 

 grooves and with feeble undulations jinrallel with the lines of growth. 

 Externally the shell is white beneath the thin, pale yellow epidermis. 



Length, 13'5'"'"; transverse breadth, (i""" ; height, from apex to 

 ventral margin, 14-5""". 



Station 2097, N. lat. 37° 50' 20", W. long. 70" 57' 30", in li)l7 

 fathoms (No. 35,203), one dead but fresh specimen. 



