MARINE MOLLUSCA OP THE UNITED STATES. 155 



central, a little prominent, posterior slope slightly concave. Pri- 

 mary teeth two in each valve ; lateral teeth very distinct. White 

 with rosaceous radiating bands, sometimes obsolete ; within tinged 

 with yellow, and showing the bands. 

 Length 2T, height 23 mill. 



Georgia, southwards. 



3. S. NEXILIS, Gould. 



Proc. Bost. Soc. Nat. Hist., viii. 280. 1862. 



Shell oblong-oval, white, with a blush towards the umbones ; 

 reticulated by concentric laminar striae and remote radiating ribs, 

 their intersections punctate, and muriculate towards the ends ; 

 umbones a little behind the middle. 



Length 25, height 15 mill. 



Coast of Georgia. 



The sculpture is similar to that in the young of Lucina tigerina, 

 but much more delicate. 



The above is from Gould's description; I have not seen the 

 species. 



4. S. ORNATA, Gould. 



Proc. Bost. Soc. Nat. Hist., vii. 280. 1862. 



Shell small, elliptical, reddish, rosaceous near the margin in 

 radiating and concentric lines ; concentrically costate-striate and 

 radiately striate ; within flavous somewhat radiated with red. 



Coast of Georgia. 



This species I have not seen. It was dredged by the U. S. 

 Coast Survey. 



Genus CTJMINGIA, Sowerby. 

 Proc. Zool. Soc., 3, 4. 1833. 



The species of Cumingia are usually found in sponges, sand, 

 and fissures of rocks; the valves, in consequence, often assume 

 an irregular aspect. 



1. 0. TELLINOIDES, Conrad. Fig. 384. 



(Mactra.) Journ. Philad. Acad., vi. 258, t. 9, f. 2, 3. 1830. 

 Shell ovate-triangular, thin, white, nearly equilateral ; pointed 

 and deflected behind, broadly rounded before; surface covered by 

 numerous sharp, elevated growth lines. 



Length 15, height 11 mill. 



New Bedford, Mass., to Georgia. 



