EASTERN PROVINCE — INTERIOR REGION SPECIES. 259 



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 be- 

 yond 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 Sewa- 

 nee, 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 orhiculata and a few 

 ribbed alternata found witk them. Mr. Lea's locality is Jasper, Marion 

 County. A species of the Cumberland Subregion. 



Jaw arched, high ; ends blunt ; anterior surface with coarse, perpen- 

 dicular striae ; cutting margin with decided median projection. 



Lingual membrane (see p. 49, Fig. 8) long and narrow. Teeth of same 

 type as in P. soUtaria, alternata, &c. 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 lat- 

 eral, &c., have them well developed. The transition to marginals is 

 very gradual, and is not formed by the bifurcation of the inner cutting- 

 point, which remains simple to the extreme outer edge. The smaller 

 outer cutting point is sometimes bitid in the outer marginals. These 

 last are usuall}^ but a simple modification of the laterals, as shown (see 

 plate) in the twentieth and thirtieth 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 spe- 

 cies. 



The genitalia agree with those of P. alternata figured by Dr. Leidy 

 in Terr. Moll., I, Plate YII, Fig. 2, excepting, perhaps, that in Cum- 

 herlandiana the genital bladder is smaller and its duct longer and nar- 

 rower. 



