286 PLANISPIRA. 



granules elongated in the direction of lines of growth. Spire 

 depressed, slightly convex ; apex obtuse. Whorls 4, gradually 

 widening, the last depressed ; deeply and abruptly descending to 

 the aperture, rounded at the periphery, very strongly constricted 

 behind the peristome. Aperture very oblique, nearly circular ; lip 

 narrowly expanded, flattened, white, upper and lower margins con- 

 tinuous across the parietal wall, the basal margin slightly thickened 

 within. Umbilicus deep, rather narrow. 



Alt. 3, diam. 7 mill. 



New Guinea. 



This species is allied to H. tuckeri Pfr. but may readily be dis- 

 tinguished from that species by the continuous peristome, more 

 oblique aperture and deeper constriction of the whorl behind the 



HP. 



Helix (Trachia) dentoni FORD, The Nautilus iii, p. 17. 

 ANCEY, The Conchologist, 1891, p. 31. Cf. Brazier in Hedley, 

 P. L. S. N. S. W. (2) vi, p. 82. 



Ancey has declared this species to be a synonym of H. cyclostom- 

 ata, but of course this is a blunder. It is much more likely that 

 Brazier is correct in saying that the range of variation in H. tuck- 

 eri will include the dentoni; but the considerable number of speci- 

 mens of tuckeri examined by Mr. Ford and myself show no transi- 

 tion forms. Brazier and Hedley believe that the specimen is from 

 Queensland, and got in among Denton's New Guinea shells 

 accidentally. It was washed out of a large New Guinea Helix by 

 a son of the lamented Wm. Denton. 



P. BAUDINENSIS Smith. PI. 58, figs. 8, 9. 



Shell discoidal, broadly, perspectively umbilicated, pale brownish. 

 Whorls 4, slightly convex, separated by a deep suture, sculptured 

 with numerous rather thick, oblique, slightly undulating ribs ; the 

 first two whorls smooth ; the last whorl having a long, rather shal- 

 low depression toward the aperture, above, constricted behind the 

 lip, and deeply descending. Aperture contracted, auriform ; peris- 

 tome whitish, slightly expanded and reflexed, having a conspicuous 

 tubercle inside and a smaller basal one. 



Greater diam. 6, lesser 5 mill. (Sw.) 



Baudin Island, N. W. Australia (J. J. Walker.) 



Helix ( Gonostomd) baudinensis SM., The Conchologist, ii, p. 97, 

 figs. 



