Perkins.] 122 [October 6, 



OVULID.E. 

 Simxia H. & A. Adams, 1853. 



Simnia tmiplicatula Adams, Gen. Rec. Moll., Vol. i, p. 373. 

 Volca uniplicatula Chenu, Man. Conch., Vol. I, p. 273, fig. 1802, 

 et aL auct. 



Dr. Nelson found a single specimen of this shell, which was proba- 

 bly brought on southern oysters, or in ballast. 



CALYPTIL&IDJE. 

 Crepidula Lam., 1799. 



Crepidula eonvexa Say, Am. Conch., p. 75, 1822; Gould, In- 

 vert. Mass., p. 160; De Kay, Moll. N. Y., p. 158, pi. vii, fig. 131. 



Littoral and Laminarian. Abundant, especially on Ilyanassa obso- 

 leta. Animal dusky; rostrum nearly as long as the tentacles, which 

 are short, cylindrical, tapering, bearing the eyes on the outer base; 

 foot round behind, auricled before, longitudinally creased. This 

 species is much more active than the two others. 



MEASUREMENTS. 



Length of shell 11.6 mill. Breadth 7.4 mill. 

 " foot 7 " "4 " 



" tentacles 3 " " of rostrum 1.6 mill. 



Crepidula fornicata Lam., An. sans Vert., Vol. vii, p. 641; 

 Say, Am. Conch., p. 73, 1822; Gould, Invert. Mass., p. 158, fig. 17; 

 De Kay, Moll. N. Y., p. 157, pi. vii, figs. 152 and 154. Patella forni- 

 cata Linne, Syst. Nat., 1257. 



Very common, varying greatly in form and color in different sta- 

 tions. It occupies the same zone with the preceding. Animal usually 

 white; mantle dark, edged with a simple yellow cord; rostrum 

 deeply bilobed, lobes round, yellow; tentacles blunt at the ends, 

 short, eyes on the outer base; foot broadly oval, dark on the edge, 

 round behind; in front bearing a long curved auricle on each side ; 

 lingual ribbon short and broad. Teeth 3-1-3 ; median tooth with a 

 central triangular denticle and a smaller one each side, the edges of 

 which are finely serrate ; inner lateral tooth broad at the end, and 

 serrate with numerous small denticles; outer teeth simple, long, 

 curved. 



