NO. 1139. DEEP-WATER MOLLUSCAVEER1LL AXI> BTSH. 805 



CUSPIDARIA PELLUCIDA (Stimpson). 



(Plates IAX V. lig. X; I AX VI, U-. 8.) 



Necerapelhtcida STIMPSOX, Invert. Grand Maiian, p. 21, pi. i, fig. 13, 1853. 

 GOULD, Invert. Massachusetts (2d ed.), p. 61, fig. 378, 1870. VEKKILL, 

 Check-list, p: 24, 1*7! I. 



Necera sp. VERRILL, Expl. AUwtroxs, Report U. S. Com. Fish and Fisheries ibr 

 1883, p. 574, 1885. 



Not Nea'ra obesa LOVKN. 



Shell small, much swollen, with a strongly tapered, somewhat pro- 

 duced rostrum. Umbos relatively large and prominent, beaks minute, 

 strongly incurved. The anterior portion is broadly and evenly rounded, 

 the margin forming nearly a semicircle, with the dorsal margin strongly 

 convex and excurved, rising nearly as high as the uuibos; the ventral 

 margin is broadly rounded but distinctly incurved at the base of the 

 rostrum which is rather narrow distally, obtusely rounded at the tip 

 and slightly upturned ; the postero dorsal margin slopes considerably, 

 is nearly straight at first but becomes slightly concave on the rostrum. 

 External surface nearly smooth but usually showing more or less prom- 

 inent lines of growth, most distinct on the distal part of the rostrum 

 which is destitute of a distinct diagonal line. The right valve has a 

 short, very prominent, strongly curved lateral tooth rising close to the 

 beak, the most prominent part being near the proximal end which rises 

 rather abruptly from the very minute cartilage plate from which it is 

 not separated by a notch; just in front of the beak, the hinge-margin 

 is distinctly thickened, sinuous, and a little prominent, forming a sort 

 of tooth, separated from the lateral tooth only by the minute sunken 

 cartilage-plate; the left valve also has a slight, sinuous thickening of 

 the margin in front of the cartilage plate. 



Length of one of the largest specimens, 4.5 mm.; height, 3mm.; 

 breadth, 3 mm.; beak to end of rostrum, 3 mm.; beak to anterior end, 

 2.5 mm. 



This species has been taken at Eastport Harbor; Bay of Fundy, near 

 Grand Man an Island; and at about twenty-one stations between N. 

 lat, 47 40', W. long. 47 35' 30", and N. lat. 35 U' L>0", W. long. 

 74 59' 10", in 52 to 516 fathoms, 1868-1886. 



The specimens here described are from the Bay of Fundy, near 

 Grand Manan Island and Eastport Harbor, very near the locality 

 where Doctor Stimpson's types were obtained. In former articles we 

 have united this species with G. obesa (Loven). A careful reexam- 

 inatiou of a large series of specimens of both forms has convinced us 

 that they are distinct but closely related species. In G. obesa the 

 anterior portion is more produced, giving the shell a more ovate out- 

 line; the rostrum is broader and rather more upturned; the cartilage- 

 plate is relatively much larger, more prominent, and angular at the 

 edge, and in the right valve is separated from the lateral tooth by an 



