294 A MANUAL OF AMERICAN LAND SHELLS. 



Jaw as usual in tlie genus ; over 14 ribs. 



Lingual membrane : Terr. Moll., Y, Plate XVI, Fig. C. 



Genitalia unobserved. 



Ti'iodopsis Van IVostrandi, Bland. 



This species is in form and character of tbe aperture very nearly al- 

 lied to iiiiroferens, but is more decidedly costate, more convex at tbe 

 Fio. 316. ^J^se, with smaller umbilicus, and without the internal tuber- 

 cle. It connects introfcrens and iniltuosa with, but is quite 

 distinct from , fa Uax. 

 T. Van Xos. rj^]^Q measurements of a specimen with Gi whorls are: 

 la.ged. Qi,(.j^t^.i. diameter 12.J, lesser 11""" ; height, 7™'". Of a speci- 

 men with G whorls: Greater diameter 10, lesser 8'"'"; height, 5"^"'. 

 (Bland.) 



Helix Van Xosfrandi, Bland, Aun. of Lye. of Nat. Hist, of N. Y., si, 200 (1875). 

 Triodoima Van Nostrandi, W. G. Binney, Terr. Moll., v, 312. 



Trobably a species of the Cumberland Subregion, though thus far 

 only noticed at Aiken, S. C, and Augusta, Ga. 



Animal long, tail pointed ; dirty white, darker on head, eye-pedun- 

 cles, and tentacles. 



Jaw as usual in Triodopsis ; ribs 17. 



Lingual membrane (Terr. Moll., V, Plate YII, Fig. I) long and nar- 

 row. Teeth 24-1-24, with 10 laterals. The centrals have no distinct 

 side cusps or cutting points, but the latter are replaced by decided 

 bulgiugs on the median cutting point. The figure gives the central, 

 with the first, tenth, eleventh, nineteenth, and twenty-fourth teeth; 

 the last two are marginals. 



Genitalia (Terr. Moll., Y, Plate XY, Fig. G) differing from those of 

 tridentata, fallax, and Hopelonensis by the swollen, elongated, oval 

 genital bladder, and by its duct, equally swollen, excepting at the base 

 of the bladder, where it is narrow. The bladder with its duct appears 

 like one long, swollen organ, with a median constriction. Six individ- 

 uals have these characters constant, but the difference is slight as a 

 specific character. 



I?IESODON, Kaf. 



Animal as in Patula; mantle suboentral. 



Shell umbilicated or with the umbilicus closed, subglobose or or- 

 bicularly depressed, thin, delicately striate, sometimes decussatedl3' 

 Kculiitured ; whorls 5-C, regular; aperture rotundly lunar, sometimes 



