36 PHASIS. 



subangular periphery. Aperture large, oblique, toothless ; peristonie 

 fragile. Type H. acanthinula Crosse, pi. 6, figs. 71, 72, 73. 



Jaw and soft parts not examined. 



Dentition : centrals as wide as long, tricuspid, the mesocone attain- 

 ing the anterior border of the basal-plate, side cusps small. Laterals 

 similar. Marginal teeth low, wide, with the entocone and mesocone 

 long, united at base, the ectocone split into three minute cusps (pi. 

 9, fig. 25, E. acanthinula. ^) 



E. acanthinula Crosse. iii, 124. New Caledonia. 



Section Tropidotropis Ancey. 



Tropidotropis ANC., Bull. Soc. Mai. Fr. v, p. 370. 



Shell broadly umbilicated, discoidal, the spire nearly flat; whorls 

 flat above, the last acutely carinated ; epiderniisjaciniate-lamellose. 

 Aperture securiform, toothless, the peristome simple, acute. Type 

 H. trichocoma Crosse, pi. 6, figs. 61, 62. 



E. trichocoma Cr. iii, 45. New Caledonia. 



Section Pterodiscus Pilsbry, 1893. 



Tropidoptera ANC., Bull. Soc. Mai. Fr. vi, p. 191. Not Tropido- 

 pterus Blanch. 1845 (Coleoptera.*) 



Shell umbilicated, depressed, thin or fragile, horny brown. 

 Whorls finely, densely striated, the last acutely keeled at the periph- 

 ery, carinated around the umbilicus. Aperture oblique, toothless ; 

 lip thin and simple. Type H. alata Pfr., pi. 4, fig. 44. 



Shells of this section have the appearance of the New Caledonian 

 groups Acanthoptyx and Tropidotropis. The species are from the 

 Sandwich Is. 



E. alata Pfr. E. depressiformis Pse. 



E. prostrata Pse. E. digonophora Anc. 



Genus PHASIS Albers, 1850. 



Phasis ALB., Die Hel., p. 92. Type and only species H. menke- 

 ana Pfr. PILSBRY, Manual viii, p. 135. 



Shell resembling Xeropliila; depressed, umbilicated, solid, white 

 and opaque, generally with brown bands or dots, the apex dark; last 

 whorl not descending ; aperture rounded-lunate, but little oblique ; 



