RHYTIDA. 123 



R. PREVOSTIANA, Crosse. PI. 28, figs. 41, 42. 



Umbilicus perforate, partly covered, thin, with subdistant 

 lamelliform striae ; yellowish brown, more or less maculated with 

 light chestnut, particularly at* the suture ; whorls 5, with im- 

 pressed suture, base subplanate and regularly costulate. 



Diam. 6, alt. 4'5 mill. 



New Caledonia. 



The color varies, sometimes uniform horny-white, or dark 

 corneous, or horny-white more or less maculated with orange- 

 brown. 





R. PTYCHOMPHALA, Pfeiffer. PL 22, figs. 16-18 ; PI. 28, fig. 39. 



Rather thin, glossy, closely, irregularly, frequently anasto- 

 mosely striated, without spiral sculpture ; olive-brown, with 

 some more or less distinct chestnut strigations, and a faint 

 yellow band around the umbilicus ; whorls 4^, the last inflated 

 and deflected at the mouth, somewhat flattened. 



Diam. 1*4, alt. *5 inch. 



Port Essington, Australia. 



Figs. 17, 18, from Kiister, represent a shell not fully grown, 

 and without the yellow umbilical band ; Pfeiffer's original de- 

 scription is based on a similar shell. I add (fig. 16) a fully 

 developed shell from Cox's work, and a smaller one (fig. 39) 

 from Reeve. 



R. LEICHARDTI, Cox. PI. 22, fig. 23. 



Widely umbilicaced, somewhat solid, closely obliquely costu- 

 late above, scaicely shining, opaque; olivaceous red; whorls 4J, 

 the last descending at the aperture. Diam. 1-4, alt. -65 inches. 



1 Australia. 

 R. STRANGEI, Pfr. PI. 22, fig. 27 ; PL 28, fig. 49. 



Umbilicated, rather thin, shining, pellucid, closely striate 

 above, decussated by very numerous impressed spiral lines ; 

 yellowish, reddish or horny chestnut, sometimes with light 

 chestnut strigations ; whorls 5, not descending in front ; base 

 nearly smooth, glossy. Diam. 1, alt. *4 inch. 



New South Wales. 

 R. LINCOLNIENSIS, Pfr. PL 22, fig. 28. 



Umbilicated, thin, strongly closely striate and slightly granu- 



