13(3 HELICEA. 







slate-color, superior tentacles darker, short, thick, bulbous ; eyes 

 large, distinct ; foot two-thirds of the length of shell ; whitish, long, 

 very narrow, rounded at tail ; body narrower than foot. 



In motion they are exceedingly graceful, at times poising their 

 beautiful shell high above their body, and twirling it round not 

 unlike the Physa, again hugging their pretty harp close to the 

 back ; the shell when in this last position continually oscillates as if 

 the animal could not balance it. It rarely ever moves in a straight 

 line, but is always turning and whisking about, and this is done at 

 times very quickly and abruptly. 



Mighel's description of Pupa costulata is as follows : 



Shell ovate-conic, scalariform, light yellowish-brown, thin and fragile, 

 whorls four, convex, the last two prominently ribbed, the first two smooth ; 

 suture distinct; aperture semicircular, slightly oblique, unarmed; lip 

 simple or modified by the last rib ; umbilicus distinct. Length, y\ inch ; 

 breadth, nearly T \y. Hab. Portland. 



BULIMUS MARGINATUS SAY vol. ii. p. 288, pi. lii. fig. 1. 



Cydostoma marginata SAY, (Binney's ed.) p. 22. 

 Bulimus maryinatus PFEIFFER, Malac. Blatt. ii. 94. 

 Bulimus fallax GOULD, in Terr. Moll. 1. c. 



STIMPSON, Shells of N. E. p. 84, (absq. desc.) 

 Pupa fallax SAY, (Binney's ed.) p. 28. 



PFEIFFER, 1. c. iii. 533. 



CHEMNITZ, ed. Nov. (1844,) p. 58, pi. 12, figs. 20, 21. 

 Pupa Parraiana ORBIGNY, Moll. Cuba, p. 181, pi. xii. figs. 9-11, (1853). 



I have retained the first specific name given by Say, at 

 the suggestion of Pfeifter, (Malak. Blatt. 1856, ii. p. 13, in 

 the review of Terr. Moll.), who justly observes that if the 

 species is referred to Bulimus, no name has the priority 

 over it, as B. marginatus Pf. is now considered a synonym 

 of B. Guillianij Petit. 



As for the name albilabris, it was suggested by Adams 

 only because marginatus was preoccupied. 



Gould (Invert. 192) considers Pupa placida Say as a 

 synonym of this species; and Pfeiffer (ii. 309) makes it 

 var. ft of marginatus. 



