338 TERRESTRIAL AIR-BREATHING MOLLUSKS. 



An Oregonian Region species, ranging from 46° to 49° latitude. It also ha3 

 crossed the Cascade Mountains, ranging southeasterly into the 

 Central Province as far as the Coeur d'Alene Mountains, and 

 Salmon River, Idaho. At the latter localities it is smaller and 

 much less globose, and has its aperture decidedly tridentate. 

 This form is figured here. It was also described by Mr. Bland 



as H. Mullani, his type being more globose. I am convinced of the identity 



of the two forms, but repeat his description and his figures. 



Helix Mullani, Bland. — Shell with umbilicus partially covered, globose-de- 

 pressed, dark horn-colored, irregularly striated, having a thin epidermis with 

 microscopic spiral lines, and tubercles (the latter with hairs ?) ; 

 beneath the epidermis shining ; spire short ; whorls 5J to 6, con- Flg ' 2 -~' 

 vex, the last gibbous above, scarcely descending, the base rather 

 smooth, much constricted at the aperture ; aperture subtriangular, 

 oblique, with a short, white, linguiform, parietal tooth ; peristome 

 white, or reddish horn-colored, thickened, expanded, and roundly 

 reflected, with 2 teeth on the margin of the callus, the lower one 

 lamelliform, the other small, often obsolete, the columella!- margin partially 

 covering the middle-sized, pervious umbilicus. Greater diameter 13£, lesser 11 

 mill. ; height, 7 mill. 



Jaw (of the Salmon River form) as usual in the genus, with 7 stout ribs. 

 The lingual membrane of the same (PI. VIII. Fig. O) has 23—1—23 teeth, 

 with 16 perfect laterals. 



Genitalia and lingual dentition of the typical form (see Appendix). 



Mesodon profunda, Say. 



Vol. III. PI. XXII. 



Shell broadly umbilicated, orbicularly depressed ; epidermis yellowish horn- 

 color, with reddish-brown, revolving lines and bands, sometimes uniformly 

 brown or albino ; whorls from 5 to 6, convex, obliquely striated with delicate 

 and regular raised striae ; suture distinct ; aperture almost circular, a little con- 

 tracted by the peristome, flattened towards the plane of the base ; peristome 

 white, thickened, reflected, with a slightly prominent callus, or obtuse tooth, on 

 the inner edge near the base; umbilicus rather large and profound, exhibiting 

 all the volutions to the apex ; base convex, with the stria? converging into the 

 umbilicus. Greater diameter 29, lesser 24 mill.; height, 14 mill. 



Helix profunda, Say, Journ. Phila. Acad., II. 160 (1821) ; American Conchology, 

 No. 4, PI. XXXVII. Fig. 3; ed. Binney, 20, 36, PL XXXVII. Fig. 3; ed. 

 Chenu, III. 51, PI. XIII. Fig. 2, b, 2, c. — DeEay, N. Y. Moll., 42, PI. III. 

 Fig. 3. — Leidy, T. M. U. S., I. 255, PI. IX. Figs. 1-3, anat. — Binney, 

 Bost, Journ. Nat. Hist., III. 377, PL XV; Terr. Moll.; II. 177, PL XXII.— 

 Pfeiffer, Mon. Hel. Viv., I. 382 ; in Chemnitz, ed. 2, II. 63, PL LXXVII. 

 Figs. 14-16. — Deshayes in Fee., I. 69. —Mrs. Gray, Fig. Moll. An., PL 



