EASTERN PROVINCE INTERIOR REGION SPECIES. 255 



A Post-Pliocene species, now very common in the Interior Region, 

 especially in the parts north of the Ohio River. I have never received 

 it from south of Missouri. It has ranged widely westward, having been 

 found in the Coeur d'Alene Mountains, in Idaho, associating with stri- 

 gosa. Thus it is the only species of the Interior Region which has 

 crossed the barrier of the Rocky Mountains. It has even passed the 

 Cascade Mountains into the Pacific Region, having been found living 

 at the "Dalles" and on "Government Island," in the Columbia River, 

 within twelve miles of Fort Vancouver, by Prof. O. B. Johnson, who 

 has sent specimens to the Smithsonian Institution, which I have myself 

 seen. 



Jaw long, low, slightly arcuate, ends but little attenuated, anterior 

 surface striate, but without ribs ; a median projection to the cutting 

 margin. 



The lingual membrane (Terr. Moll. U. S., V, Plate IV, Fig. K) has 

 25-1-25 teeth, with 14 perfect laterals. The transition to marginals 

 is very gradual. 



The anatomy of this species is figured by Leidy {I. c). The genitalia 

 present several peculiar features (see Terr. Moll. TJ. S., I, Plate VIII, 

 Fig. 8). The penis sac (5) is short, stout, receiving near its apex the 

 retractor muscle (6), above which it rapidly decreases in size, and at 

 its apex receives the vas deferens (2) ; the last-named organ is very 

 peculiar in being greatly convoluted before entering the penis sac; the 

 genital bladder (9) is small, globular, on a long duct, which becomes 

 swollen at its lower end 5 the epididymis (2) is convoluted in its entire 

 course. 



Patula alternata, Say. 



Shell broadly umbilicated, orbicularly depressed, thin, smoky horn- 

 color varied with red, interrupted, obliquely arranged fig. 2G9. 

 patches and spots, roughened by crowded, elevated, 

 rib-like striae, smoother below; whorls 5i, flattened, 

 the last sometimes obtusely carinated at its perii)hery ; 

 umbilicus large, pervious; aperture very oblique. In- 

 nately rounded, banded within; peristome simi)le, 

 acute, its terminations joined by a very tbin, trans- 

 parent callus, that of the columella subreflected. • 

 Greater diameter 21, lesser 19"""; height, 10""". r- aiternata. 



