66 INVERTEBRATA OF MASSACHUSETTS. 



with two small cardinal teeth in each valve ; palleal impression with 

 a deep sinus. 



SANGUINOLA'RIA FUSCA. 



Shell compressed, ovate-orbicular, sub-equilateral, rounded be- 

 fore and somewhat pointed behind ; white, covered with a dusky 

 epidermis ; teeth two in each valve, the largest of which is grooved. 



FIGURE 42. 

 State Coll., No. 212. Soc. Cab., No. 1754. 



Psammobia fusca, SAY; Journ. Acad. Nat. Sc., v. 220. 

 Sanguinolaria fusca, CONRAD ; Atner. Mar. Conch., 34, pi. 7, f. 1. 

 Tellina inconspicua ? SOWERBY ; Zool. Journ., iv. 359. 

 Tellina Gronlandica, BECK. 

 Tellina Balthica, LIN. 



Shell thin, white, compressed, ovate-orbicular, nearly equi- 

 lateral, height nearly equal to length, rounded before, somewhat 

 narrowed and pointed behind ; beaks minute ; an imperfect ridge 

 or fold runs from the beaks to the posterior termination ; surface 

 finely wrinkled by the lines of growth, covered by a whitish or 

 dusky epidermis ; ligament exterior ; two unequal, parallel teeth 

 in each valve, the large one opposing the small one in the other 

 valve, and deeply groved or cleft ; muscular impressions distinct. 

 Length TV inch, height ^ inch, breadth /? inch. 



This is one of our most abundant bivalve shells. It is thrown up 

 on every beach, and appears to live everywhere in shallow, still water. 

 Multitudes appear in the mud which is obtained about Boston at low 

 tide for raising wharves, extending the land, &c. 



Its varieties in size, strength, and color, are very great. In muddy 

 bays they grow to a large size, are thick, and of a bluish or sometimes 

 a rusty color, and are covered with a firm, dark epidermis. In clean, 

 sandy localities they are very delicate and thin, pure white, or some- 

 times of a delicate rose-color or lemon-color, and the' epidermis is 

 very slight. 



All recent authors, except Deshayes, agree in calling this a San- 

 guinolaria. 



It is undoubtedly identical with Tellina Gronlandica of Beck ; and 

 it certainly is very like, if not identical with, Sowerby's T. inconspicua, 

 published in the " Zoological Journal." The young, delicate, white, 

 or rose-tinted ones accord in every respect with T. BdUhica. 



