GASTEROPODA. 161 



Alderia harvardiensis Gould. 



Gould, Inv. Mass., 1870, p. 254, pi. 16, figs. 226-228. " Cam- 

 bridge, [Mass.]." 



Mass. — " Found in great numbers, in brackish waters, at 

 Cambridge, April, 1848" (Agassiz); Cohasset in marsh creeks. 



ELYSIIDAE. 



Elysia chlorotica Gould. 



Gould (A. Agassiz MS.), Inv. Mass., 1870, p. 255, pi. 17, figs. 

 251-255. " Cambridge [, Mass.]." 



IVIass. — Found in great numbers in brackish water on the 

 Cambridge marshes, in the spring of 1848 (Agassiz) ; Cohasset on 

 eel-grass; Duxbury. 



Elysia (Elysiella) catula (Gould). 



fPlacobranchus simplex Girard, Proc. Boston Soc. Nat. Hist., 

 1854, vol. 5, p. 89. 



Placobranchus catulus Gould (A. Agassiz MS.), Inv. Mass., 1870, 

 p. 256, pi. 17, figs. 249, 250. " East Boston." 



Elysiella catulus Verrill, Amer. Journ. Sci., 1872, ser. 3, vol. 3, 

 p. 284, pi. 7, figs. 5, 5a; Rept. Inv. Vineyard Sound, 1873, pp. 480, 

 668, pi. 25, fig. 171. 



Elysia catulus Apgar, Journ. Trenton (N. J.) Nat. Hist. Soc, 

 1891, vol. 2, p. 129, pi. 3, fig. 26. 



Mass. — " Channel near East Boston, January, 1848 " (Agassiz); 

 Chelsea Beach (Girard); Woods Hole, adhering to eel-grass; 

 Duxbury. 



Conn. — New Haven. 



LIMAPONTIIDAE. 



Limapontia zonata (Girard). 



Gould, Inv. Mass., 1870, p. 258. 



Niobe zonata Girard, Proc. Boston Soc. Nat. Hist., 1852, vol. 4, 

 p. 211. " Boston Harbor, [Mass.]."" 



