Molluscan Fauna of New England. 283 
same, 
Stylifer Stimpsonii V., sp. nov. 
Shell white, short, swollen, broad oval; spire short, rapidly 
enlarging. Whorls four or five, the last one forming a large 
part of the shell; convex, rounded, with the suture impressed, 
surface smooth, or with very faint strie of growth; a slightly 
impressed revolving line just below the suture. Aperture large 
and broad. Length about ‘15 of an inch; breadth ‘12. I have 
seen no specimens with the aperture perfect. 
Off the coast of New Jersey, on a bank in 32 fathoms, para- 
sitic on Huryechinus Drébachiensis V.,—Capt. Gedney. 
Cecum costatum V. Plate v1, fig. 6. 
Cecum Cooperi Smith, Annals Lyceum Nat. History, vol. ix, p. 394, fig. 3, 1870, 
(non Carpenter). 
Mr. Sanderson Smith has described and figured this shell in 
a later stage of growth than the one here figured. my fig- 
ure the longitudinal costz are, by an error, not so distinctly 
brought out as they should be, and the annular grooves 1n the 
Beeston are too distinct. 
n the adolescent stage of growth pase at enlarges rather 
rapidly, and has 12 or 13, distinct, elevated, rounded coste, nar- 
rower than the intervals between; the circular grooves are 
numerous, unequal, interrupted over the costw, and broader 
toward the aperture. The aperture is rounded within ; its mar- 
gin is externally stellated by the coste. yaoat 
Vineyard Sound, 8 to i0 fathoms—A. E. V.; Gardiner's 
Bay, L. ., 4 to 5 fathoms, sand,—Smith. 
ELYSIELLA, gen. nov. 
Allied to Elysia and Placobranchus. Head rounded, os 
two short, obtuse tentacles; eyes sessile behind the bases of the 
tentacles, on the neck. Lateral lobes united behind, rounded 
* The figure in Gould’s Tavertebrata (copied in the new edition) is very poor. 
