124 NEW-YORK FAUNA — MOLLUSCA. 



FAMILY TROCHIDJE. 



Animal with two contractile tentacles : eyes at their external bases, pedunculated. Marine 

 and jluviatile. Shell very variable in form ; aperture occasionally with its edges dis- 

 united, but not forming a canal, and but rarely with a sinus in front. 



(EXTRA-LIMITAL.) 



Genus Ampullaria, Lamarck. Shell globular, ventricose, umbilicated: aperture oblong, entire; 

 margins united: no callosity on the pillar-lip. Lip acute, not reflected. Anopercle. Aquatic, 

 fluviatile. 



A, hopetonensis. (Lea, Tr. Am. Phil. Vol. 5, pi. 19, fig. 84.) Shell smooth, flattened above, umbi- 

 licate, banded; sutures impressed; whorls five; aperture subovate. Color, yellowish or dusky 

 brown; aperture white. Length, 1-7; diameter, 1*4. Georgia. 



A. rolundata. (Say, Des. terr. & fluv. shells, p. 22.) Shell very globose ; spire little elevated ; body- 

 whorl undulated, instead of being wrinkled ; aperture on the margin within, thickened equally all 

 round, with a slight groove for the opercle ; umbilicus small, narrow. Length, 1 • 8 ; width, 1 • 8. 

 Florida. 



A. paludosa et depressa. (Say, Exped. St. Peter's, Vol. 2, p. 264, pi. 14, fig. 2. A. paludosa, Id. 

 MSS. penesma et disseminata.) Whorls four, slightly wrinkled; body-whorl more prominent 

 above, somewhat flattened towards the suture ; spire very much depressed ; aperture oval, exhibit- 

 ing the bands on the margin ; umbilicus small, nearly closed. Color, pale olivaceous, obsoletely 

 banded with obscure green, with numerous vertical and transverse greenish and brown lines; 

 aperture somewhat glaucous. Length, 1-5; of aperture, 1 • 2. Ilorida. 



GENUS JANTHINA. Lamarck. 



Animal with a large head and extended snout, with the mouth at its extremity ; the latter with 

 two vertical cartilaginous lips, armed with long recurved spines. Tentacles two, conic, 

 pointed, distant, and scarcely contractile. Eyes beneath the extremities of moderately 

 long peduncles, which arise from the outer base of the tentacles. Foot oval, in two por- 

 tions : the anterior concave and sucker-shaped ; the posterior flattened, thick and fleshy. 

 Swimming appendages lateral, broad and fringed, consisting of a congeries of vesicles. 

 Breathing cavity patulous, with two branchial pectinated series ; orifice of the ovaries in 

 this cavity : male organ small, on the right side. Shell thin, brittle, globular or conoidal, 

 ventricose ; spire low ; aperture angular at the junction of the lips beneath ; pillar-lip 

 twisted; lip with a sinus at the middle : all the species yet known, of a violet color. Opercle 

 represented by a vesicular appendage attached to the posterior portion of the foot. 



