V0 188^"'] PROCEEDINGS OF THE NATIONAL MUSEUM. 273 



margin are sometimes broken up into short segments, and on the oppo- 

 site valves of the same specimen there are usually perceptible but not 

 constant differences in the sculpture, which is fully reflected on the 

 polished interior of the delicate valves; ligament thin, short; lunular 

 area long, very narrow, smoother than the rest; rostrum transversely 

 striated with two or three obscure radial ridges, the most anterior of 

 which forms the boundary behind which the waved sculpture does not 

 pass; interior polished, scars of adductors obscure; pallial sinus deep, 

 rounded, reaching to or into the anterior third of the shell ; teeth small, 

 .short, simple in the young, grooved on their outer surface in the adult, 

 the single tooth in the left valve showing the grooving most strongly. 

 Maximum longitude of shell, 12.5; altitude, 0; diameter, 3 mm . 



Hab.— U. S. Fish Commission Station 2823, in latitude 24° 18' K, 

 longitude 110° 22' W., off the coast of Lower California, in 26£ fathoms, 

 fine sandy mud. 



This interesting little shell gapes, if at all, but slightly and only at 

 the tip of the rostrum. 



Cyinatoica orientalis sp. nov. 

 Plate x, Fig. 12. 



Shell white, thin, resembling the last species, but with the beaks 

 more central and less pointed, the posterior end broader at the more 

 vertical truncation and less rostrate, the valves slightly flatter and the 

 wavy sculpture distinctly augulated at an oblique line radiating from 

 the beaks somewhat forward; there are no visible radii on the rostrum, 

 but the wavy sculpture does not pass forward of a diagonal from the 

 beak to the lower posterior angle-of the shell; the lunular area is wider 

 and more deeply impressed than in C. occidentalism and the posterior 

 end of the shell is less strongly flexed. Maximum longitude, 9.5; alti- 

 tude, 5.5; diameter, 3 ,mn . 



Hab.— Samana Bay, Santo Domingo, in 16 fathoms, mud, Couthouy ; 

 also in the same depth at Cardenas, Cuba, from T. H. Aldrich, esq. 



This little shell has been many years in my hands awaiting a name. 

 When an analogous species appeared in the Fish Commission collec- 

 tions from the Pacific it seemed a suitable occasion to put them on 

 record together. The wavy sculpture in this species is sometimes a 

 good deal broken up anteriorly. 



Subgenus MACOMA s. s. 

 Macoma brevifrons Say. 

 Tellina brevifrons Say, Am. Conch., vn, PI. 64, Fig. 1, 1834. 



The shell, which I have identified as the true brevifrons of Say, 

 though with some hesitation, agrees well, when young, with Mr. Say's 

 description and passably well with his figure. The latter is usually 

 on the plate colored so that it does not agree with the text, which was 

 published after Mr. Say's death. The adult shell is proportionally longer 

 Proc. N. M. 89 18 



