142 HELIX. 



rounded, and banded with brown; sutures linear, slightly impressed; 

 aperture very oblique, transversely ovate, dark brown within; peri- 

 stome reflexed, white, bearing a strong basal tooth ; outer lip with a 

 strong denticle. Diam. 25 mill. 



Southern Oran, Algiers. 



The tubercles are strong, and situated so near to each other as to 

 leave but a narrow space between them. 



The synonyms are If. tigriana Bourg. and H. maresi Crosse. If. 

 stereodonta Bourg. (PL 43, figs. 68, 69) H. dicallistodon Bourg. (PL 

 42, figs. 66, 67,) and H. surrodonta Bourg. (PL 43, figs. 70, 71,) seem 

 to be too closely allied to the H. tigri to warrant separation as dis- 

 tinct species. 



H. DASTAGUI Bourguignat. PL 43, fig. 72. 



Imperforate, depressed, solid, striate, white, with four brown 

 zones ; spire slightly convex ; whorls 5 to 6, rather rapidly increas- 

 ing, the last descending anteriorly ; aperture oblique, oblong-lunate, 

 white within, with a lamelliform denticle within the outer lip and 

 a heavy tubercle at the base ; peristome expanded, slightly labiate. 



Diam. 27 mill. Southern Oran, Algiers. 



Specimens occur in which the umbilicus is not wholly covered. 



H. SUBJOBAEANA Kobelt. PL 46, figs. 54-56. 



Shell depressed-globose, covered umbilicate, irregularly rudely 

 striate, solid, unicolored grayish white ; spire slightly elevated, short 

 conoid, apex smooth, white; whorls 5, subconvex, with distinctly 

 impressed sutures, slowly increasing, the last a little widened, not 

 angulate, rather flat below, anteriorly subcontracted and suddenly, 

 deeply deflected; aperture very oblique, small, semiovate, com- 

 pressed, and still more contracted by two strong teeth, margins of 

 peristome joined and apparently continuous by a thick parietal 

 callus, outer margin with two teeth, the outer lamelliform, the inner 

 tubercular ; inside of aperture in fresh specimens brownish. 



Diam. 23*, alt. 13* mill. 



Chott el Tigri, on the boundary of Morocco. 



A curious form, closely allied to the following. 



H. JOBAEANA Crosse. PL 46, figs. 57-59. 



Imperforate, subglobose, obtusely angulate, smooth, slightly 

 striate, shining, solid ; sutures linear, becoming impressed ; whorls 

 5, the last obtusely angulate, base convex, deeply, suddenly, deflexed 

 anteriorly ; aperture small, very oblique, ovate, contracted, peristome 



