798 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL. xx. 



Family ASTARTID^. 



ASTARTE NANA (Jeffreys?) Dall. 



Aatarte nana DALL, Bull. Mus. Comp. Zool., XII, p. 261, pi. vn, figs. 6a, 6ft, 1886; 

 Bull. U. S. Nat. Mus., No. 37, p. 46, pi. vn, figs. 6a, 66, 1889. 



* 



A single valve, which agrees perfectly with Ball's figures, quoted 

 above, was found at station 2307, off Cape Hatteras, North Carolina^ 

 in 43 fathoms, 1884. South to Sombrero, in 22 to 196 fathoms. Dall. 



Family CUSPID ARID^E. 



In the classification of this family we have adopted the groups pro- 

 posed by Messrs. W. H. Dall and E. A. Smith as defined by Mr. Dall. 1 



We, however, consider his two subgeneric groups, Cardiomya and 

 Halonympha, as distinct genera. 



CUSPIDARIA UNDATA Verrill. 



(Plates LXXII, fig. 1; LXXVIII, figs. 3, 4.) 



Nefrra undata VERRILL, Traus. Conn. Acrid., VI, pp. 223, 277, 1884; Expl. Alba- 

 tross, Report U. S. Corn. Fish and Fisheries for 1883, p. 574, 1885. 



Not Myonera undata DALL, Bull. Mns. Comp. Zool., XII, pp. 302, 304, 1886; Bull. 

 U. S. Nat. Mus., No. 37, p. 68, 1889 (in part). 



Three live specimens and two valves were found at stations 2098 and 

 2566, off Chesapeake Bay, in 2,221 and 2,680 fathoms, 1883 and 1885. 



Fragments obtained by the Blake near Havana, Dominica, and St. 

 Vincent, in 450 to 611 fathoms, are erroneously referred by Mr. Dall to 

 this species. Our shell is certainly not a Myonera. 



We have a fragment of a left valve from station 2655, N. lat. 27 22', 

 W. long. 78 7' 30", in 338 fathoms, found among Foramiuifera, which 

 belongs to a strongly undulated species, with a short, angular, sub- 

 acute rostrum defined below by a rather dee]) groove at which the 

 concentric sculpture changes abruptly. The beak is prominent and 

 turns strongly backward. The cartilage-plate is strong, deeply con- 

 cave, and directed backward; a moderately elevated internal rib runs 

 backward from the umbonal region to the posterior muscular scar. 

 The shell is thin aud has deep internal grooves corresponding to the 

 external ridges. Judging by the lines of growth, the shell was short- 

 ovate, broadly rounded anteriorly, aud having posteriorly a short, 

 angular, subacute rostrum ; the escutcheon is concave and well-defined 

 by a small, sharp ridge. This fragment seems to belong to an unde- 

 scribed species of Myonera. It can, however, hardly be the same as 

 Mr. Dall's species, as he states that in his "there is no buttress or 

 appearance of an internal rib." 



'Bull. Mus. Comp. Zool., XII, p. 292, 1886; XVIII, p. 441, 1889. 





