

1898.] NATURAL SCIENCES OF PHILADELPHIA. 229 



b. Sole not in the least tripartite ; posterior portion of 

 the tail peculiarly modified and capable of self-ampu- 

 tation ; kidney with a large excavation exposing both 

 chambers of the heart ; epiphallus more or less swol- 

 len, suddenly constricted and bent near its insertion 

 in the atrium, with which it communicates byashort 

 pedicel which is bound to the swollen portion of epi- 

 phallus by a muscular band ; vagina functional as a 

 penis ; ovo-testis lying in front of the posterior loop 

 of the gut, Peophysaon. 



b'. Sole tripartite, the narrow median field defined by 

 longitudinal grooves ; tail normal ; kidney covering 

 the auricle (seen from below) ; genitalia unknown, 



Anadentjlus. 



iii. descriptions of genera and species. 



Genus BINNEYA J. G. Cooper, 1863. 



Binneya Cooper, Proc. Cal. Acad. Sci., Ill, p. 62. 



Xatitkonyx Crosse & Fischer, Joum. de Conchyl.. XV, 1867, p. 223; Moll. 

 Terr, et Fluv. Mex., I, p. 192. Strebel & Pfeffer, Beitrag zur Kenntniss der 

 Fauna Mexikanischer Laud- und Siisswasser Conch vlien, Theil IV, p. 26 

 (1880). 



Somewhat slug-like, with elevated, subspiral visceral hump and 

 external shell, subcentral on the back ; mantle broadly produced 

 beyond the shell, not reflexed over it at edges ; breathing pore sub- 

 median or behind middle of right margin of mantle, a small rounded 

 left and somewhat larger right cervical mantle lobe on each side of 

 it; genital orifice behind the right tentacle; foot radially grooved 

 and reticulate above, the foot-margin narrow ; pedal grooves deep, 

 without a tail pore ; sole tripartite, the areas separated by longitudi- 

 nal grooves; shell Vitrina-shaped, with the first (nepionic) whorl 

 distinctly demarked from the following, and strongly sculptured. 



Viscera elevated into the dorsal hump, the body cavity not ex- 

 tending back of it into the tail, which is solid. 



Jaw arcuate, with numerous ribs denticulating the basal margin. 



Radula with 28-1-28 to 31-1-31 teeth (in B. notabilis), 32- 

 1-32 (in B. cordovan us), the rachidian teeth tricuspid, laterals bi- 

 cuspid, the ectocones small ; marginal teeth bicuspid, the inner cusps 

 moderately long, sometimes bifid. 



Intestinal tract (PI. XI, fig. 31) short; anterior loop formed by 

 G 2 and G s somewhat twisted, posterior loop of G 3 and G* straight 



