1G4 



LAND AND FRESII-WATER SHELLS OF N. A. [PART I. 



Helix arrosa, Gould, in litt. ; Otia, 215. — W. G. Binnet, Proc. Acad. Nat. 



Sci. Philad. 1857, 185 ; Terr. Moll. IV, 15, pi. Ixxvi, f. 4.— Pfeiffek, 



Mon. Hel. Viv. IV, 350. 

 Afjlaja arrosa, Tkyon, Am. .Jonrn. Conch. II, 311, pl. v, f. 10 (1867). 



Fig. 283. California ; Santa Cruz to Mendocino 



County (Cooper). 



Jaw arcuate, of uniform breadth through- 

 out ; ends blunt ; anterior surface with a 

 few (six) rather distant, stout ribs crenu- 

 lating both margins. 

 Lingual membrane with 180 rows of 54 — 1 — 54 teeth each; 



Jaw of Helix arrosa. 



Fig. 284. 



Lingual dentition of Helix arrosa. 



centrals long, conical, with a conical apex, laterals of same shape 

 uncini large, irregularly denticulated or obtusely serrated. 



Locality. 



California. 

 Columbia River. 

 San Fianci-'co. 



Petal ume. 



Near San Francisco. 



From whom received. 



Dr. Newberry. 

 Rev. J. Rowel 1. 



Cab. series. 



Var. 5 Cab. series 



Fic 285. 



Helix townsendiaiia, Lea. — Shell nmbilicated, depressed- 

 globose ; epidermis yellowish and brownish horn-color, more or less inter- 

 mixed ; snture distinct ; whirls five and a half, 

 with minute, impressed, longitudinal striae, 

 which can scarcely be traced by the eye, and 

 coarse, oblique wrinkles and striae ; body-whirl 

 large, voluminous, rough, and corrugated ; aper- 

 ture rather large, somewhat rounded ; peristome 

 white, fully reflected at the base, and but par- 

 tially so towards its superior part, thickened 

 Helix townsendiann. , ,. , . . ,, . , , 



and a little projectinsr internally in the base 



of the aperture ; umbilicus open, deep, a little contracted by the retlectiou 



