164 TERRESTRIAL AIR-BREATHING MOLLUSKS. 







University Place, Franklin County, Tennessee ; Jasper, Marion County, 

 Tennessee : a species of the Cumberland Subregion. 



Animal dirty white, darker towards the tail, the top of the head and eye- 

 peduncles, which last are dark slate-colored ; foot about the length of the 

 lesser diameter of the shell, with a darker submarginal line as in alternata, and 

 terminating in a flattened, broad, spade-like extremity like the Zonites. When 

 in motion none of the animal protrudes beyond the shell behind (looking from 

 above), before, there is but little visible, about as long as the diameter of the 

 last whorl ; the breadth of the animal before the shell is about one half the 

 same diameter. 



Found at University Place, Franklin County, Tennessee, now Sewanee, on 

 the Cumberland Mountain table-land by Bishop Elliott (1860). It is limited 

 at that place to a very small space on one of the "benches " of the mountains. 

 In habit they resemble Cylindrella and Cyclostoma, living in the crevices of 

 precipitous rocks, over the faces of which they may be found walking after 

 rains. Helicina orbicitlata and a few ribbed alternata found with them. Mr. 

 Lea's locality is Jasper, Marion County. 



Jaw arched, high ; ends blunt; anterior surface with coarse, perpendicular 

 stria? ; cutting margin with decided median projection. 



Lingual membrane (PL IV. Fig. D) long and narrow. Teeth of same type 

 as in P. solitaria, alternata, etc. The centrals and laterals have, however, a 

 much shorter median cusp. Side cusps subobsolete, and side cutting points 

 wanting on the centrals and first two laterals, the third lateral beginning to show 

 them ; the outer laterals, as the seventh lateral, etc., have them well developed. 

 The transition to marginals is very gradual, and is not formed by the bifurca- 

 tion of the inner cutting point, which remains simple to the extreme outer edge. 

 The smaller, outer cutting point is sometimes bifid in the outer marginals. 

 These last are usually but a simple modification of the laterals, as shown (see 

 plate) in the 20th and 30th teeth. There are 30 1 30 teeth, with hardly 

 13 laterals, and certainly not so many absolutely perfect ones. 



In P. alternata there are decided prominent side cusps and cutting points to 

 centrals and first laterals. The shape of the centrals and first laterals also in 

 alternata is quite different from those of this species. 



The genitalia agree with those of P. alternata figured by Dr. Leidy, in Vol. I. 

 PL VII. Fig. 2, excepting, perhaps, that in Cumberlandiana the genital bladder 

 is smaller, and its duct longer and narrower. 



Patula perspectiva, SAY. 

 Vol. III. PL XXX. Fig. 1. 



Shell broadly and perspectively umbilicated, orbicular, scarcely convex above, 

 excavated below, thin, reddish horn-color, regularly ribbed ; whorls 6^, gradu- 

 ally increasing ; aperture small, lunately subcircular, within furnished with a 



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