262 MODULUS-RISELLA. 



part radiately maculated with chestnut, the base minutely punctate. 

 Diam. 2 mill. 



Nexv Caledonia. 



Unfigured Species. 

 M. OBLiQuus, A. Ad. Red Sea- 



M. DUPLiCATUS, A. Ad. Hab. unknown. 



M. KREBSii, Morch. West Indies. 



M. CONVEXIOR, M. pisuM, M. cANALicuLATus, (Beck) Morch. 



West Indies. 

 Genus RISELLA, Gray, 1840. 



R. MELAxosTOMA, Gmel. PI. 49, figs. 99, 3-29 ; PI. 50, figs. 30, 31. 



Conically elevated or depressed, with rounded, somewhat tuber- 

 culated periphery on the elevated specimens, acutely carinated on 

 the depressed ones, radiately ribbed above, or nearly smooth, spi- 

 rally striate, most distinct on the base ; yellowish or olivaceous 

 brown, more or less articulated with chestnut, sometimes obliquely 

 longitudinally strigate, aperture dark chocolate color, varying to 

 orange brown, lip brown spotted. Length, 15 mill. 



South Australia, Tasmania. 



a. aurata, Quoy (fig. 6), E. imhricata, Gray (figs. 8, 9), R. Kiel- 

 manseggi, Zelebor (fig. 7), R. vittata, Phil. (figs. 28, 29), R. lutea, 

 Quoy (fig. 3), R. plieatula, Phil. (figs. 24, 25), R. cicatricosa, Jonas 

 (figs. 4, 5), R. nana, Lam. (figs. 99, 13, 14), R. picta, Phil. (figs. 16, 

 17), R. plana, Quoy (figs. 10, 11, 12), 7?. llvida,Fhi\. (figs. 30, 31), 

 R. Australis, Gray, R. grisea, Phil. (figs. 18, 19), R. fi.mbrlata, Phil. 

 (figs. 26, 27), R. fiavescens, Phil. (figs. 22, 23), R. Bruni, Crosse, 

 (fig. 15), and probably R. crassa, Danker, are all synonyms. 



In the range of varieties presented by this assemblage, we find 

 the shell high, with a roundly angular periphery, or low with a 

 sharp periphery, all degrees of development of tlie radiating ribs- 

 sometimes entirely wanting, or re})laced by color strigations, etc. I 

 have endeavored, in vain, to eliminate distinct or even varietal 

 forms, and at last put them all together. This was practically 

 done ten years ago by Rev. J. E. Tenison Woods (Proc. Linn. Soc. 

 N. S. Wales, i, 242, 1876), and more recently Mr. E. A. Smith 

 (Zool. Alert Ex})ed., p. 62), has partially concurred. The collec- 

 tion of specimens before me is sufficiently large and varied to give 

 me abundant evidence in support of the Australian conchologist's 



