GONOSTOMA. 149 



No specimens of H. lenticular is approach this species in 

 sculpture. 



H. WALKERI Ponsonby. PL 34, figs. 79, 80, 81. 



Shell openly and deeply umbilicated, depressed, carinated, the 

 spire depressed-conic, narrow whorled, apex fine, lightly flattened ; 

 rather thin, pellucid, deep horn-brown. Whorls 8, very slowly 

 increasing, a little convex, separated by an impressed linear suture ; 

 pretty regularly sculptured with arcuate, subdistant riblets. Last 

 whorl not dilated, convex on the base and striatulate, having an 

 acute but scarcely compressed carina ; not descending in front. 

 Aperture very oblique, crescentic, angulate outwardly; peristome 

 thin, margins distant, joined by a very slight parietal callus, upper 

 margin straight, basal reflexed, lightly white-lipped, columella 

 impressed in the umbilicus, hardly dilated at the insertion. (Kob.*) 



Alt. 8, greater diam. 14, lesser 13 mill. 



Near Esmir, coast of Morocco. 



H. (Gonostoma) walker Pons. MSS., KOBELT, Nachr. D. M. Ges. 

 1889, p. 140; Kossrn. N. F. iv, p. 79, t. Ill, f. 663. WESTERL. 

 Fauna Paliiarct. Binnenconch. suppl., p. 14. 



This is probably a variety of H. tarnieri in which the peripheral 

 keel extends entirely around the body- whorl to the aperture. 



H. SUPRACOSTATA Kobelt. PL 34, figs. 76, 77, 78. 



Shelt narrowly and nearly covered umbilicate, acutely carinated, 

 convex above and below, lenticular, convex above and very dis- 

 tinctly sculptured with rather distant curved riblets; inflated-con- 

 vex and smoother, striatulate below ; corneous-whitish covered with 

 a deciduous brown cuticle. Spire regularly depressed-convex, apex 

 minute, corneous. Whorls 7-8, slightly convex, very slowly increas- 

 ing, separated by an impressed suture crenulated by the riblets ; last 

 whorl scarcely wider than the penultimate, begirt by an acute 

 obsoletely serrated carina, inflated beneath, hardly descending in 

 front. Aperture oblique, irregularly rhomboidal, narrow, deeply 

 lunate ; peristome biangulate (lower angle less distinct), upper mar- 

 gin slightly thickened, outer margin straight, lipped within and 

 more or less distinctly toothed, basal margin reflexed subarcuate, 

 impressed in the umbilicus nearly covering it. (Kob.~) 



Alt. 7, diam. 13 mill. 



Mis. of Beni Hoznear, near Tetuan, Algieria. 



