AGLAIA. 351 



on the four outer whorls, the lower surface dark chestnut, sometimes uniformly 

 black; suture distinct, impressed; whorls 7, rounded, spirally striate, with 

 minute, delicate, impressed lines, the stria? of increase very distinct; peristome 

 reflected below, simple above, thickened ; aperture ovate, banded within ; um- 

 bilicus open, a little contracted by the reflection of the peristome ; base flat- 

 tened-convex. Greater diameter 34, lesser 30 mill. ; height, 20 mill. 



Helix fidelis, Gray, Proc. Zodl. Soc, July, 1834, 67. — Pfeiffer, Mon. Hel, 

 Viv., I. 338 ; in Chemnitz, ed. 2, I. 321, PI. LVII. Figs. 12, 13. — Mullet,, 

 Syn. Test., anno 1834 promulg., 8 (1836). — Reeve, Con. Icon., No. 6f>7 

 (1852). — W. G. BlNNEY, Pac. R. R. Rep., VI. Ill (1857) ; Terr. Moll., IY. 

 14 ; L. & Fr.-W. Sh., I. 161 (1S69). 



Helix Nuttalliana, Lea, Am. Phil. Trans., YI. 88, PI. XXIII. Fig. 74 ; Obs., 

 II. 88 (1839) ; Trosciikl, Arch. f. Nat., 1839, II. 229. — Binney, Bost. Joum. 

 Nat. Hist., III. 369, PI. XII. (1840) ; Terr. Moll., II. 159, PI. XVIII. — 

 DeKay, N. Y. Moll., 46 (1843). —Gould, U. S. Expl. Exped. Moll., 66, 

 Fig. 38 (1852). 



Aglaja fidelis, Try-on, Am. Joum. Conch., II. 311, 8 (1866). 



A species of the Oregonian Region, found from Humboldt Bay, California, 

 to Vancouver's Island, and westward to the Cascade Mountains From Mt. 

 Shasta the specimens are half as large as usual. 



Animal : color dull ochre, slaty towards the tail ; coarsely granular upon the 

 neck, but from a line running from the dorsal line, where it issues from the 

 shell, to the mouth, the granules diminish, and are succeeded by coarse, undu- 

 lating, interrupted ridges, radiating in every direction from the aperture, and 

 terminating in a line nearly marginal ; edge simple. 



This species varies in coloring. The form figured has its upper surface 

 dirty white, with oblique, longitudinal, dark blotches and a revolving dark 

 band, below uniformly dark chestnut. Another form is like this, excepting 

 that the dirty white is replaced with light chestnut or with dark chestnut. 

 There are also forms where the dark chestnut prevails over the whole shell, 

 the band being sometimes obsolete, and where the chestnut is sometimes re- 

 placed by uniform black. The upper surface is, however, usually lighter than 

 the lower ; the band when present is usually edged with white. The peri- 

 stome is always light-colored. The uniform dark form can hardly be distin- 

 guished from A. infumala, sharing also the peculiar sculpturing of that species. 

 Indeed, there are grave reasons for suspecting that fidelis and infumala will 

 prove one and the same species. 



Jaw (see above). 



The lingual membrane (PI. IX. Fig. C) has 48 — 1 — 48 teeth, with 15 later- 

 als, the sixteenth tooth having a split inner cutting point. The first marginal 

 is shown as also an outer marginal. 



The genitalia of fidelis and infumala are almost ^exactly similar. In both the 

 penis sac is extended into a decided flagellum. The vas deferens enters below 

 the flagellate extension. The retractor muscle is attached on the opposite side 



