VALVATA. 9 



deposits her eggs in a single, coriaceous, spherical capsule, which 

 is affixed to stones or the stems of aquatic plants. Jaws present. 



Valvata tricariiiata, Say. — Shell with three volutions; three 

 revolving, carinate, promineut lines, giving to the whirls a quadrate instead 

 of a cylindric appearance. Suture canaliculate, in consequence of the 

 whirls revolving below the second carina and leaving ah interval. Spire 

 convex, apex obtuse. Umbilicus large. Carinae placed, one on the upper 

 edge of the whirl, one on the lower edge, and the third on the base beneath. 

 Breadth one-fifth of an inch. 



Inhabits the river Delaware. Rare. Found by Mr. Le Sueur, whose 

 proposed name is here adopted. {Say.) 



Cyclostoma tricarinata, Say, J. Acad. N. S. Phil. 1, 13, 1817 ; Nich. Ency. 



ed. 3 ; Binney's ed. p. 68, 59, 56. 

 Valvata tricarinata, Say, Journ. Acad. 11,173; Binney's ed. 68. — De- 

 SHAYES in Lam. VIII, 507 ; Tr. El. de Conch, pi. Ixxii, f. 4-6.— Menke, 

 Zeit. f. Mai. 1845, p. 121,— Haldeman, Hon. Ill, pi. i, f. 1-4.— Gould, 

 Invert. 225, f. 150.— DeKay, N. Y. Moll. p. 118, pi. vi, f. 130. An- 

 onymous,- Can. Nat. II, 213, fig. — Adams, Thompson, VI, 152. 

 Valvata carinata, Sowerby, Gen. Shells, xli, f. 2. 

 Valvata unicarinata, DeKay, N. Y. Moll. 118, pi. vi, f. 129. 

 Valvata hicarinata, Lea ? Tr. Am. Phil. Soc. IX, 21 ; Obs. IV, 21 ; Proc. 



II, 81, 83 ; Arch. f. Nat. 1843, II, 129. 

 Tropidina carinata, Chenu, Man. de Couch. II, 312, fig. 2232. 



Troschel (Gebiss der Schnecken, p. 96, pi, vi, f. 14) figures 

 the lingual ribbon of this species. 



Fig. 12. 



Lingual dentition of Valvata tricarinata. 



This is a very variable species, as shown by No. 8981 of the 

 collection. Variety 8imj)lex is contained in ^o. 8982 ; 

 bicarinated forms in 8941. Mr. Say's specimens of 

 Valvata tricarinata are still preserved in the collection 

 of the Philadelphia Academy of Natural Scieftces. 

 From an examination of them and of Mr. Lea's origi- 

 nal Valvata hicarinata I am convinced of the identity 

 of the two. I have given (fig. 1.3) a figure of Mr. Lea's shell and his 

 description below. Haldeman refers it with doubt to tricarinata. 



I have not seen authentic specimens of the other species men- 



