HELIX-PEDINOGYRA. 15 



A very variable form in size and coloration. The lip is sometimes 

 entirely black. The largest specimen before me measures, alt. 23, 

 greater diam. 80, lesser 61 mill. ; the smallest, alt. 18, greater diam. 

 47, lesser 37 mill. 



H. MUHLFELDTIANA Pfeiffer. PI. 2, figs, 35, 36. 



Shell discoidal, smaller, duller, darker colored and more carinated 

 than H. cunninghami. 



Broadly umbilicate, convex above, solid, opaque, lusterless, 

 chocolate-colored, lighter brown on the spire; sculpture as in cun- 

 ninghami but less distinct. Whorls 5, a little convex, the last very 

 broad, carinated at the periphery, compressed above and below the 

 carina, descending about to the carina at the aperture, and flattened 

 or excavated behind the columellar lip; aperture subhorizontal, 

 truncate oblong, white within, the peristome not thickened, chocolate 

 -colored, scarcely expanded. Umbilicus very wide, showing all the 

 whorls. 



Alt. 19, greater diam. 58, lesser 42 mill. 



Alt. 16, greater diam. 47, lesser 36 mill. 



Richmond River, N. S. Wales, Australia. 



H. muhlfeldtiana PFR., Proc. Zool. Soc. London, 1852, p. 156; 

 Monographia iii, p. 157 ; Conchylien Cabinet, p. 393, 1. 143, f. 26-28. 

 Cox, Monogr. Austr. Land Sh., p. 53, t. 6, f. 2. H. rotabilis, 

 KEEVE, Conch. Icon., f. 361. 



Smaller than H. cunninghami, of a nearly uniform dull chocolate 

 or chestnut-brown color. The mouth is white inside but the lip is 

 broadly edged with dark brown. It is nearly allied to the cunning- 

 hami, but I have seen no intermediate specimens. 



H. CANALICULATA Pfeiffer. Unfigured. 



Shell orbicular-ovate, very widely umbilicate, depressed, a little 

 convex, very thin, fragile, subhyaline, epidermis yellowish-brown, 

 beneath yellowish-green ; spire obtuse ; whorls 5, convex ; separa- 

 ted by a profound, channeled suture ; obliquely very densely, 

 deeply, undulately striate, the strise wrinkle-like on the under 

 surface, separated, irregular, very delicate ; under a lens seen to be 

 Tery densely concentrically striate ; umbilicus large, dilated to the 



