770 GASTROPODA. \_Pulmounln. 



very easily rubbed off. Spire elevated conic, a little higher than the 

 aperture. Protoconch globose. Whorls 5, convex, the last rapidly 

 increasing, ventricose ; base rounded. Suture impressed, faintly and 

 narrowly margined. Aperture subvertical, ovate, angled above. Peri- 

 stome thin, sharp. Outer Up moderately convex ; basal lip naii/ower 

 arched. Columella vertical, not twisted. Inner lip thin, broadly re- 

 flexed above, and partly concealing the very narrow and not deep 

 perforation ; parietal wall with an entering median small lamella. 



Diameter, 2-2 mm. ; height, 3-5 mm. 



Animal unknown. 



Type in my collection. 



//a&. Whangarei, type (C. Cooper) ; near Auckland (H. S.) ; 

 Raoul Island, Kermadec Islands (Miss Shakespear). 



Tribe 2. AGNATHA. 



Agnatha, Simroth, Ueber die Raublungenschnecken : Naturw. Wochenschrift, 

 1901, Nos. 10-12. 



No jaws ; the radular teeth narrow and pointed ; carnivorous. 



Fam. RHYTIDIDJE, Pilsbry. 



Animal with the mantle not or but very little reflected over the 

 shell, without a caudal pore ; no jaw ; teeth of radula aculeate ; 

 mostly oviparous, but species are known to be ovoviviparous. 



Shell heliciform or auriform, generally umbilicated, with depressed 

 or plane spire, and simple peristome. 



The fanrly includes the genera Rhytida, Paryphanta, Schizoglossa, 

 Delos, Diplomphalus and Natalina. 



Distribution. New Zealand, Tasmania, Australia, New Guinea, 

 New Caledonia, Polynesia, South Africa. 



KEY TO GENERA. 



a. Shell of medium size ; umbilicus infundibular ; surface stri- 



ated, rugose, or malleated ; periphery convex or keeled ; 



peristome simple, sharp . . . . . . . . RHYTIDA. 



b. Shell mostly large, umbilicated or perforated ; epidermis 



shining, sometimes coriaceous ; periphery convex ; epi- 

 dermis extending beyond the peristome ; shell sometimes 

 flexible . . . . . . . . . . . . PARYPHANTA. 



c. Shell small, rudimentary, auriform, worn on the tail of the 



animal . . . . . . . . . . . . SCHIZOGLOSSA. 



'/. Shell small, widely umbilicated, polished ; whorls 3^4, rapidly 

 increasing ; periphery convex ; epidermis not involving 

 the peristome . . . . . . . . . . DELOS. 



Genus 1. RHYTIDA, Albers, 1860. 



Rhytida, Albers, " Die Heliceen," ed..2, 1860, 89. Type : Helix Greenwoodi, 

 Gray. 



Animal having the neck, tail, and sides of body irregularly granular, 

 the tail flattened and pointed, foot somewhat narrow ; mantle with 



