168 HELIX-HELICELLA. 



close acute riblets ; white, beautifully ornamented with bands and 

 streaks of chestnut; spire conoid, apex minute, projecting, buff. 

 Whorls 6, slowly increasing, separated by a linear, hardly impressed 

 suture, convex ; last little dilated, angulate at the periphery, rounded 

 at the base, and slowly passing into the umbilicus ; produced in 

 front but hardly descending. Aperture very oblique, subangulate, 

 ovate, moderately lunate ; peristome acute, thin, straight, lipped with 

 white inside ; the margins converging, hardly connected, columellar 

 margin very slightly dilated at the insertion. (Kob.) 



Alt. 11, greater diam. 17, lesser 15 mill. 



Neighborhood of Hamman Rirha, eastern foot of the Zaccar, 

 Algiers. 



H. calida KOB., Rossm. Icon. n. f. iv, p. 78, f. 661. 



H. ZACOARENSIS Kobelt. PI. 38, figs. 5-13. 



Shell moderately and deeply umbilicate, depressed globose, solid, 

 little shining, ribbed-striate above, the riblets close ; smoother 

 beneath ; sculptured here and there with short impressed lines. 

 Whitish having an interrupted median chestnut band and numerous 

 brown lines ; spire depressed-conoid or conoid, apex small, smooth, 

 brown, little projecting ; whorls 6, regularly increasing, the suture 

 at first linear, then irregularly crenulated ; upper whorl slightly con- 

 vex, hardly carinated, the last inflated, subcyliudrical, the base con- 

 vex, abruptly passing into the umbilicus, scarcely descending in 

 front, slightly dilated. Aperture oblique, lunate-circular ; peristome 

 thin, acute, straight, narrowly and rather remotely lipped with 

 white within; margins converging, connected by a very thin callus ; 

 columellar margin slightly dilated at the insertion. (Kob.~) 



Alt. 14, greater diam. 2T8, lesser 18'5 mill. 



Alt. 12J, greater diam. 18'5, lesser 16'5 mill. 



On cliffs of the western Zaccar Peak, near Miliana, Algeria. 



H. zaccarensis KOB., Rossm. Icon. n. f. iv, p. 77, f. 660. 



Nearly allied to H. calopsis, but somewhat more narrowly umbil- 

 icated, having no, trace of a keel, and more weakly sculptured. 



H. FABRIESI Debeaux. PI. 38, figs. 19, 20. 



Shell openly and deeply umbilicate, depressed trochiform, with 

 the spire conoid ; apex minute, slightly obtuse, black ; rather solid, 

 chalky, little shining; all over densely and irregularly ribbed- 

 striate ; last whorl with the exception of the tract immediately 



