1869.] 145 [Perkina. 



Not very common. Lives in a few feet of water, buried in sand. 

 Animal white ; mantle open, fringed with short papillae; gills serrate 

 on the edges ; foot when contracted curved below, above curved to 

 a sharp point anteriorly, and more abruptly curved behind, grooved 

 below ; palpi triangular, not long, striated coarsely inside ; siphons 

 distinct, long, slender. 



Angulus polita? Tryon, Am. Journ. Conch., Vol. in, pt. v, 

 p. 94, App. Tellina polita Say, Am. Conch., p. 97, 1822; De Kay, 

 Moll. N. Y., p. 210. 



A few specimens have been found which are somewhat doubtfully 

 referred to this species. 



Peronea Poli, 1791. 



Peronea tenta Tryon, Am. Journ. Conch., Vol. in, pt. V, p. 98, 

 App. Tellina tenta Say, Am. Conch., p. 228, pi. lxv, fig. 3, 1822 ; 

 Gould, Invert. Mass., p. 68, fig. 43; De Kay, Moll. N. Y., p. 210. 



Very rare. 



Macoma Leach, 1819. 



Macoma fusea Stimps., Check List. Psamobia fusca Say, Am. 

 Conch., p. 126, 1826. Sanguinolaria fusca Gould, Invert. Mass., p. 

 66, fig. 42 ; De Kay, Moll. N. Y., p. 212, pi. xxxii, fig. 304. 



Very large and abundant. It thrives best in water that is not very 

 salt, and is much larger and more abundant near the mouths of fresh 

 water streams than outside the harbor. It lives in sand or mud, just 

 beneath the surface, below, or near low water. Animal white; man- 

 tle open in front, edge ruffled and bordered with dark brown ; gills 

 •small, one on each side; foot tongue -shaped ; when extended nearly 

 as long as the shell; palpi triangular, large; siphons very long and 

 slender, when extended nearly twice as long as the shell. The ani- 

 mal moves quite briskly by jerking itself along with its foot. 



MEASUREMENTS. 



Length of shell 17 mill. Breadth 13.8 mill. Height 6.6 mill. 



ventral siphon 25 " " 3 « ? at base> 



" dorsal " 17 " " 2 " > 



foot 12 " " 11 " 



Some of the specimens are 41 mill, long by 32 broad. 



PROCEEDINGS B, S. X. H.— VOL. XIII. 10 DECEMBER, 186$, 



