PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 399 



whole surface of the shell. The shell itself is rather large, swollen, 

 subovate, well-rouuded ventrally, but obliquely subtruncate anteriorly. 

 Eostrum rather short, narrow, well detined, tapered ; on the rostrum 

 there are eight or nine rather broad, low, radiating costai. The body of 

 the shell is covered with regular, raised and strong, radiating costae, 

 over fifty in number, separated by deep grooves of about the same 

 width as the costai; anteriorly these ribs become small; posteriorly, 

 near the base of the rostrum, five or six become much larger than the 

 rest, and have smaller ones alternating with tliem. 



Color yellowish white ; in life rosy, from the internal organs showing 

 through. Length, 19"""; beak to ventral edge, 12'"'". 



South of Martha's Vineyard, 115 fathoms ; about 90 to 100 miles 

 south of Newport, 85 to 120 tathoms, stations 871, 873, 874, 876, &c. 

 Several living specimens of various sizes. 



Cardium, sp. 



A roundish species of Cardium, about 18""" in diameter, is represented 

 by a single valve, in good condition. The surface is rather closely and 

 regularly cancellated. The ribs are smooth, without scales or spines. 

 It was taken at station SG5. 



Astarte crenata Gray. 



Parry's Voyage, app. — Friele, Catal. Norv. Nordmeer-Exp. Spitzb., Moll., p. 



267, 1879. 

 f Astarte erehricostata Forbes; .Jeifreys; G. O. Sars; and otlier European 



writers. 

 Astarte erehricostata Gould, Invert., Mass., 2d ed., p. 126, fig. 440 (var. lens). 

 Astarte lens (Stimp., MSS.) Verrill, Amer. Journ. Set., iii, p. 287, 1872. 



Large numbers of specimens, which seem to agree closely with the 

 typical arctic and deep-water form of this species, were taken at nearly 

 all the stations, in G5 to 500 fathoms. It was most abundant at stations 

 880, 891, 895. 



These form series that appear to graduate into the large, broad, flat- 

 tened form to which the name lens has been applied, which is abundant 

 in the Bay of Fundy and Gulf of Maine, in 50 to 150 fathoms. 



The typical form is smaller, more swollen, with the edges more 

 ronnded, and less expanded posteriorly. All the forms have the edges 

 regularly crenulated. 



Cryptodon Sarsii (Pbil.). 



AxhiHs Sarsii G. O. Sars, op. cit., p. 60, pi. 19, figs. 5 a, h. 



A single dead specimen of a shell agreeing very closely with this 

 form, as figured by G. O. Sars, was dredged by our party, in 1879, off' 

 Cape Cod. 



Cryptoa obesus Verrill. 



Amer. Journ. Sci., iii, p. 287, pi. 7, fig. 2, 1872. 



I may take tbis occasion to remark that Sars's figure (pi. 19, fig. 7) of 

 C. ohcsus Verrill does not represent the large form described by me 

 under that name, which is remarkable not only for its swollen form, but 



