212 PROCEEDINGS OF THE ACADEMY OP 



RissoiNA DEBiLis, Garr., pi. 2, fig. 9. 



Shell elongate, slender, white ; spire long, rapidly tapering from 

 the body whorl ; whorls 8, convex, the last one rounded, longi- 

 tudinally ribbed ; ribs small, slightly oblique, rounded, flexuous 

 on tlie body whorl ; interstices transverselj'- striated with fine 

 raised lines, which are larger and continuous at the base ; suture 

 deeply impressed ; aperture oblique, sub-oval, about two-sevenths 

 the lengtli of the shell ; peristome much thickened externall3\ 



Length 4^ mill. 



Hub. Viti Isles. (Coll. Garrett.) 



A very rare species found under clumps of coral on reefs. 



RissoiNA AFFiNis, Garr., pi. 2, fig. 10. 



Shell elongate-oblong, rather solid, smooth, shining, white; 

 spire moderately elevated, obtuse, somewhat rapidly' tapering ; 

 whorls 7-8, convex, the last one large, swollen, slightly com- 

 pressed ; suture linear ; aperture large, oblique, ovate, one-third 

 tlie length of the shell; peristome very thick, dilated, sinuous 

 above and beneath ; columella and parietal region callous. 



Length 5 mill. 



Hub. Viti Isles. (Coll. Garrett.) 



A rare species belonging to the same group with R. curta, tri- 

 dentala and oryza. 



KissoiNA TEREBRA, Garr., pi. 2, fig. 11. 



Shell solid, elongate, subulate, ashy-white, with or without a 

 revolving brown band ; spire long, acute, tapering from the body 

 whorl; eml)ryonal whorls 2, smooth, normal whorls 10, convex, 

 longitudinallj^ strongly ribbed; ribs slightly oliliqiie, angular, 12- 

 13 in the penultimate whorl ; interstices with minute crowded 

 raised transverse striae, which are most conspicuous towards the 

 base ; suture deeply impressed ; aperture small, oblong-oval, 

 oblique, less than a fourth the lengtli of the shell ; peristome 

 trenchant on its edge, externally strongly varicose ; columella and 

 parietal region with a white callus. 



Length 8^ mill. 



Hah. Viti and Samoa Isles. (Coll. Phil. Acad. Nat. Sciences.) 



A rare species of which we found four examples under clumps 

 of coral on reefs. 



