Rissomas. 93 



1 Mauritius [type] ; coll. G. Nevill, Esq. 



One of the most remarkable species of the Genns. 



SECTION G. ZEBINA, H. and A. Adams. 



Gen. Moll. I, p. 328, 1855, type E. coronata, Secltiz ; = Group F7, 

 Schivartz, I. c., page 39. 



75. Rissoina tridentata. 



Kissoa tridentata, Michaud^ . Descr. Coq. nouv. 1832 ; fide Schwartz, long. 

 8, diam. 4 mil., from lied Sea, Philippines, Mauritius and Sandwich I. ; 

 Suez, fide M' Andrew ; fide Pease = R. crassilabrum, Garrett, 1857 ; 

 from Tahiti, fide Graffe. 



2 N. Caledonia; ex. c. P. Bouvier, Esq. 



1 Roweiah, Red Sea ; coll. J. B. Baxter, Esq. 

 12 Mauritius [9 T V, 5], Andamans and Ceylon ; coll. G. Nevill, Esq. 

 4 Sandwich Islands; coll. H. Pease, Esq. [64, 3*]. 



76. Rissoina coronata. 



Rissoina coronata, Secluz, ms., Schwartz, Denies. K. Ale. Wissen. Wien, 

 XIX, I860, Mauritius, long. 5 3, diam. 2'3 mil. ; 1 = R. Udentata, Phil., 

 and var. from Vpolu,fide Schmeltz, 1. c. V. 



1 Mauritius ; coll. G. Nevill, Esq. 



E. affinis, Garrett, P. Ac. Phil. 1873, Viti Is., long. 5 mil., 

 must be close to this species ? 



77. Rissoina bidentata. 



Rissoa bidentata, Phillipi, Wiegm. Arch. 1845, p. 64, Friendly Isl., 

 long, f, diam. 1% ; fide Schwartz, long. 6'5, diam. 2'8 mil., Mauritius 

 and Friendly Islands. 



3 Mauritius [5|, 2] ; coll. G. Nevill, Esq. 



Besides the dentition of the aperture, the differences in the 

 shape of the spire, whorls, &c., easily and certainly distinguish 

 it from It. tridentata. 



