1869.] 159 [Perkmn. 



anteriorly it is heeled, and when drawn into the shell is folded upon 

 itself; palpi large, thick, triangular ; siphons united, not long, ends 

 not fringed, and withdrawn at times entirely within the edge of the 

 mantle. 



PECTINID^}. 

 Pecten Brug., 1789. 



Pecten irradians Lam., An. sans Vert., Vol. vn, p. 143. Pec- 

 ten concentricus Say, Am. Conch., p. 88, 1822; Gould, Invert. Mass., 

 p. 134, fig. 88; De Kay, Moll. N. Y., p. 172, pi. xi, fig. 205. 



Usually not common, and very small, but sometimes it is thrown 

 upon the shore in great numbers. Animal very active, jumping and 

 swimming by a rapid opening and closing of the valves; mantle 

 open, edge much thickened, with an outer fringe of several rows of 

 papillae, the inner being largest, and among them about thirty bluish 

 ocelli, of various sizes and at unequal intervals; inside of these, from 

 a tenth to a quarter of an inch, according to the size of the animal, 

 is a raised yellow cord, darker than the mantle, which bears a row 

 oi papillai ; the space between the inner and outer rows is thickly 

 striated ; gills semicircular, curving about the large muscle, rather 

 broad and thick; foot very small, subcylindrical, tapering to an ob- 

 tuse point, very deeply grooved; palpi broadly triangular, smooth 

 outside, obliquely striated within. 



OSTREIM3. 

 Ostrea Linn., 1758. 



Ostrea virginica Lam., An. sans Vert., Vol. vu, p. 225; De 

 Kay, Moll. N. Y., p. 169. Oslrea virginiana Gould, Invert. Mass., p. 

 136. 



The southern oyster is brought here in great quantities and planted 

 in the spring, to be taken up in the fall, as it cannot endure the cold 

 of winter. By many writers it is regarded as the same as Ostrea 

 canadensis Lam. 



Ostrea borealis Lam., An. sans Vert, Vol. vn, p. 220 ; Gould, 

 Invert. Mass., p. 137; De Kay, Moll. N. Y., p. 169, pi. x, fig. 204. 



Native or northern oyster. It is quite abundant, in some places 

 forming large beds. It is very variable in shape, accommodating 

 itself to any unevenness of the surface on which it grows. I found, 



