Its 



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



callosity (sometimes wanting), and almost covering the umbilicus. Greater 

 diam. 26, lesser 23 ; height 18 mill. 



Helix areolata, Sowekby, Brit. Mus. — Pfeiffek in Zeitschr. f. Mai. 1845, 

 II, lU ; Mon. Hel. Viv. I, 152 ; in Chemnitz, ed. 2, I, 248, pi. 

 xxxvi, f. 10-13.— Philippi, Icon. II, 15, p. 184, pi. ix, f. 4 (1847).— 

 Gould, Terr. Moll. Ill, 15.— W. G. Binney, Terr. Moll. IV, 19, pi. 

 ixxvi, f. 3, 11. — Reeve, Con. Icon, 664. 



Polymita areolata, Tryon, Am. Journ. Conch. II, 319, pi. vi, f. 5 (1866). 



Arionta veitchii, Tkyon, Am. Jouin. Conch. II, 316, pi. v, f. 19 (1806). 



The specimens figured are from Cerros Island, California. Tlie 

 species is also quoted from Oregon, and is referred by ISiewcomb 

 to Margarita Bay. 



Helix tryoni, Newcomb. — Shell imperforate, globose-conic, solid, 

 with distant, deep, strong revolving lines cutting through the strife of in- 

 crease, of a bluish ash color above, mottled with 

 Fig. 312. irregular oblique patches of brown, and with a 



median revolving line of dark brown, below dirty 

 white ; spire conic ; apex obtuse, smooth, shining, 

 light horn-color ; whirls five to six, scarcely con- 

 vex, the last globose, descending towards the aper- 

 ture, inflated below ; aperture oblique, subcircular, 

 small, within dark above, lighter below ; peristome 

 Helix tryoni. thickened, dirty white, its terminations somewhat 



converging, joined by a light callus, right margin 

 slightly expanded, not reflected, that of the columella dilated, scarcely 

 reflected, appressed, obtusely subdentate. Greater diam. 24, lesser 20; 

 height 14 mill. 



Helix tryoni, Newcomb, Proc. Cal. Acad. Nat. Sci. Ill, 116 (1864).— W. 



G. Binney, Am. Journ. Conch. I, 47, pi. vi, f. 1-10 (1865)^ 

 Polymita tryoni, Tryon, Am. Journ. Conch. II, 319, pi. vi, f. 3 (1866). 



San Clemente Island and San Nicholas Island, California. 



Jaw arcuate, of uniform width throughout, ends blunt ; anterior 

 surface with stout ribs, denticulating either margin. Figures of 

 the jaws of nine mature individuals are given, showing that the 



