RISSOINA. 389 



K. PERCRASSA, Nevill. PI. 59, figs. 38, 51. 



Solid, shining, white ; whorls about 12, the earlier normal ones 

 longitudinally costate, afterwards smooth, suture narrowly margined ; 

 lip thickened, smooth within, externally varicose. 



Length, 12' 5 mill. 



Upolu, Tahiti, Mauritius. 



R.percrassa (fig. 38), was described from a Mauritian specimen, 

 abnormal in possessing a strong callous thickening of the lower 

 part of the body whorl ; subsequently, what appears to be a normal 

 growth of the same species was described by Nevill under the name 

 of R. Peasiana (fig. 51). 



K. INSIGNIS, Ad. and Reeve. PI. 59, figs. 40, 33. 



Solid, white, or tinged with yellow ; whorls 5, subgradate, the 

 upper ones longitudinally costate, the others spirally striate ; lip 

 thick, crenulated within. Length, 9 mill. 



Red Sea, Indian Ocean, China, Society Islands. 



The last locality is for R. turrita, Garrett (fig. 33). The figure 

 and the type specimen do not exhibit the interior crenulations of 

 the lip, but they are mentioned in Garrett's description, and prob- 

 ably the latter was drawn from a more adult specimen than the one 

 sent for illustration. 



Section ZEBINA, H. and A. Adams. 1854. 



R. TRIDENTATA, Mich. PI. 59, figs. 41-44, 39, 54 ; PI. 68, fig. 14. 



Solid, smooth, polished, white, whorls 7, almost plane, the upper 

 ones sometimes costate, suture simple; lip subdilated, thickened, 

 not varicose, tridentate, bidentate, or unidentate within, sometimes 

 without teeth. Length, 8 mill. 



Red Sea, Philippines, Mauritius, Viti and Sandwich Is. 



It is JR. curta, Sowb. Ms., R. cra^silabrum, Garrett (fig. 14), R. 

 semiylabrata, A. Ad. (fig. 39), R. bidentata, Phil. (fig. 42), R. coro- 

 nata, Recluz. (fig. 43), R. eulimoides, A. Ad. (fig. 44), and R. semi- 

 plicata, Pease (fig. 54), not adult. 



R. AFFINIS, Garrett. PI. 59, fig. 62. 



Rather solid, smooth, shining, white, spire elevated, rapidly 

 tapering ; whorls 7-8, slightly convex, the last swollen, slightly 

 compressed, suture linear; lip very thick, dilated, sinuous above 

 and below, columella and parietal region callous. Length, 5 mill. 



Viti Islands. 



