114 PLANISPIRA. 



peristome expanded, reflexed below, not toothed, margins approach- 

 ing and joined by a parietal callus. Type P. cyrtopleura, pi. 19, figs. 

 20, 21, 22. 



Distribution, South Australia. Anatomy unknown. 



This group contains snails allied to the P. tuckeri group of the 

 islands off the north coast of Australia, but modified by the condi- 

 tions of life in an arid region. Still it is doubtful whether the separa- 

 tion of the two groups serves any useful purpose. 



Species. 



P. cyrtopleura Pfr., iv, 65. P. eyrei Ad. & Ang., iv, 66. 



P. phillipsiana Ang., iv, 66. P. subsecta Tate, iv, 66. 



Section Trachiopsis Pilsbry. 



Trachiopsis PiLSi, Manual of Conch, viii, p. 284. 



Shell small, depressed, umbilicated, the whorls rather cylindrical, 

 covered with a brown cuticle, the last deflexed in front and more 

 or less constricted behind the lip. Aperture round or angular, 

 oblique, the lip thin, well expanded or reflexed, sometimes toothed. 

 Type P. tuckeri Pfr., pi. 19, fig. 18, 19. 



Anatomy unknown. These small Planispira-like shells have 

 hitherto been classed in Trachia, an Indian group. They inhabit 

 the northern coast of Australia and adjacent islands. It is doubtful 

 whether this group should be separated from Angasella. It differs 

 mainly in the lighter, thinner texture of the shell, and the tendency 

 to form a tooth upon the basal lip. 



P. tuckeri Pfr. iv, 65. P. delessertiana LeGuill., iv, 66. 



strangulata H. & J. taranaki Gray. 



P. cyclostomata LeGuill., iv, 65. torresiana H. & J. 



P. dentoni Ford, viii, 285. P. endeavorensis Braz., P. Z. S. 



P. dryanderensis Cox, P. Z. S., [1871, 640. 



[1872, p. 19. P. baudinensis Smith, viii, 286. 

 P. collingii Smith, viii, 287. 



Subgenus TRACHIA Albers, 1860. 



Trachia ALB., Die Hel., edit. 2, p. 160. STOLICZKA, Journ. 

 Asiat. Soc. Beng. xl, (2), p. 223 (anatomy). Eurystoma ALB., Die 

 Hel. 1850, p. 126 ; edit. 2, 1860, p. 129, type H. vittata. Cf. SEMPER, 



