HELIX. 



1T5 



Fig. 304. 



Helix gabbi, Newcomb. — Sliell subperforate, depressed-globose, thin, 

 smooth, very delicately striated, dirty white, darker above, with a median 

 revolving, white-margined brown band ; spire little elevated ; 

 whirls five, rather convex, the last flattened globose, descend- 

 ing at the aperture ; aperture lunately rounded, oblique ; peri- 

 stome white, thickened, somewhat reflected, the columellar 

 portion almost covering the umbilicus. Greater diam. 10, 

 lesser 8 ; height 5 mill. 



Helix fjahbii, Newcomb, Proc. Cal. Acad. Nat. Sci. Ill, 117 



(1SG4). 

 Aglaja gahhii, Tkyon, Am. Journ. Conch. II, 315, pi. vi, f. 



19 (186G) ; III, pi. xi, f. 31 (1867). 



Helix c/ahbi. 



Fig. 305. 



San Cleraente Island, California. 



Under the name of H. temd^triata (certainly not 

 of Binney) I have received a shell from Catalina 

 Island, apparently a less developed form of H. gahbi. 

 It is here figured. 



Helix facta, Newcomb. — Shell imperforate or sub- tenuisMnta 

 perforate, globose or depressed-globose, smooth, shining, 

 surface hardly broken by delicate incremental striae and revolving lines, 

 light fawn color above, below lighter, with a median, white- 

 margined, revolving band of a darker colored hue ; spire Fig. 306. 

 elevated, apex obtuse ; whirls five to six, rather convex, the 

 last slightly descending, globose ; aperture oblique, banded 

 within ; peristome thickened, brownish, shining, its inner 

 margin rounded, reflected, the columellar portion dilated, 

 appressed, partially or entirely covering tlie umbilicus. 

 Greater diam. 14, lesser 12 ; height 8 mill. 



Helix facta, Newcomb, Proc. Cal. Acad. Nat. Sci. Ill, 118 



(1S64). 

 Aglaja facta, Tryon, Am. Journ. Conch. Ill, 1G2, pi. xi, f. Helix facta. 



32 (1867). 



Sta. Barbara Island, California. On this and San Nicolas 

 Island is found a larger, heavier, extinct variety. 



Jaw arcuate, of equal breadth throughout ; an- 

 terior surface with distant, stout ribs, denticulating 

 either margin. 



Lingual membrane with 114 rows of 29 — 1 — 29 

 teeth ; centrals long, stout, obtuse, laterals long, 

 acutely pointed with a short side-cusp, becoming modified and 

 merging into wide irregularly-pointed uuciui. 



Fig. 307. 



