On the Mbllusca of Long Island. 157 



loaded with vegetation, sometimes of twenty times its own bulk, 

 and I at first supposed that the color of the shell was due to a 

 film of this, but such does not appear to be the case. [The 

 same circumstance was noticed in some specimens of Tectura 

 testudinalis, taken at the same time, in which the shell was 

 distinctly green by transmitted light, though the animal ap- 

 peared colorless.] Among specimens taken in the beginning 

 of February from the same locality, were several which had 

 the upper surface of the body, as well as the tentacles, dark 

 grey to jet black. In these, as well as the light colored ones, 

 the green tint was visible along the edges of the operculigerous 

 lobe, as in those taken in November. Circumstances prevented 

 any examination of the question of the correspondence of these 

 differences with sexual distinctions. This species appears to 

 exclusively inhabit very shallow water here, as I have never 

 found it alive in dredging, and very rarely dead. 



38. Hissoa minuta Stimpson. Extremely abundant dead, in 

 some localities mixed with Yenus geinma. Found alive, rarely, 

 under stones at low water mark, and abundantly in mud at 

 two fathoms. 



39. Rissoa Siimpsoni {n. s. ?). Shell thin, rather dark brown. 

 Divergence about 24°. Whorls seven, very convex, separated 

 by a very deep suture, and distinctly wrinkled by the lines of 

 growth. Apex obtuse. Aperture oval, nearly one-third the 

 length of the shell. Length -23 in., of which the first whorl 

 occupies rather more than one half. Only two specimens were 

 found. Mr. Stimpson thinks it new, but suggests that it may 

 possibly be a giant form of ^. minuta^ which it resembles in 

 form, though darker colored and much larger. 



40. Skenea {n. s. ?). About Ij of an inch long. Mr. Stimp- 

 son thinks it new. Only one specimen was found, which is in 

 a state that will hardly admit of a satisfactory description. 



41. Calyptrea striata Say. Only one dead specimen was 

 picked up on one of the beaches in Gardiner's Bay. About 

 Montauk Point a number of specimens were found, though it 



