GASTEROPODA. 



Synonym, Tebennophorus, Binney. 



Animal elongated, convex, tapering behind, entirely covered 

 by a thin mantle ; respiratory orifice near the head ; jaw smooth. 

 ISTo shell. 



Distribution, 9 species. North America. 



Sub-genus : — Meghimatium, Hasselt. Syn., Incilaria, Benson. 

 Body depressed, rounded at the end. 



Distribution, 4 species. Java, Chusan. 



Family IY. — Limist^id^.* 

 PoMPHOLYX, Lea, 1856. 



Etymology, pompholux, lat. bulla. 



Type, P. eflFusa, Lea. Sacramento river, California. 



Shell gibbosely rounded, drawn back beneath, flattened 

 above, imperforate ; spire depressed ; aperture very large, 

 nearly round, efiuse ; outer lip acute, inner lip thickened, 

 flattened. 



Animal with two long tentacles, bearing eyes, and a second 

 pair of eyes at the base on the inner side of the tentacles. 



Distribution, 2 species. Western America. 



PiTHABELLA, Edwards, 1860. 



Type, P. Eickmani, Ed. "Woolwich and Eeading Series," 

 Peckham and Dulwich, London. 



Shell partaking of the characters of Limncea and Chilinia, 

 subcylindrical ; aperture oval, rounded in front, narrowed 

 behind ; columella straight, or very obliquely twisted, arched 

 anteriorly ; outer lip simple, acute ; inner lip thickened. 



The species is associated with estuarine shells, remains of 

 mammals and terrestrial plants. 



YALEisrciEisnsrEsiA, Eosseau, 1842. 



Dedicated to the late Professor Yalenciennes of Paris. 



Type, Y. annulatus, Eos. ; associated with fresh- water shells 

 in a tertiary deposit, near Kertch, Crimea. 



Shell resembles a gigantic Ancylus ; apex much incurved ; 

 surface concentrically marked. A longitudinal plication 

 extends from the apex to the right border, and corresponds 

 with an internal channel ; there is a second but less distinct 

 plication on the left side. 



Camptonyx, Benson, 1858. 

 Type, C. Theobaldi, Bens. Guzerat. 



* See p. 300. 



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