RISSOIDE. 93 
1 Mauritius [type]; coll. G. Nevill, Esq. 
One of the most remarkable species of the Genus. 
Section G.—Zepina, H. and A. Adams. 
Gen. Moll. I, p. 328, 1855, type R. coronata, Recluz;=Group VI, 
Schwartz, 1. ¢., page 89. 
75. Rissoina tridentata. 
Rissoa tridentata, Michaud, Deser. Cog: nouv. 1832; fide Schwartz, long. 
8, diam. 4 mil., from Red Sea, Philippines, Mauritius and Sandwich I. ; 
Suez, fide MAndrew; fide Lease=R. crassilabrum, Garrett, 1857 ; 
from Tahiti, fide Greffe. 
2 N. Caledonia; ex. c. P. Bouvier, Esq. 
1 Roweiah, Red Sea; coll. J. B. Baxter, Esq. 
12 Mauritius [925 5), Andamans and Ceylon ; ne G. Nevill, Esq. 
4 Sandwich Islands; coll. H. Pease, Esq. [63, 
76. Rissoina coronata. 
Rissoina coronata, Recluz, ms., Schwartz, Denks. K. Ak. Wissen. Wien, 
XIX, 1860, Mauritius, long. 5:3, diam. 23 mil. ;?=R. bidentata, Phil., 
and var. from Upolu, fide Schmelz, l. c. V. 
1 Mauritius ; coll. G. Nevill, Esq. 
R. affinis, Garrett, P. Ac. Phil. 1873, Viti Is. long. 5 mil, 
must be close to this species P 
yee 
77. Rissoina bidentata. 
Rissoa bidentata, Phillipi, Wiegm. Arch. 1845, p. 64, Friendly Isl., 
long. 2, diam. 18 ; fide Schwartz, long. 6°5, diam. 2:8 mil., Mauritius 
and Friendly Islands. 
3 Mauritius (58, 24]; coll. G. Nevill, Esq. 
Besides the dentition of the aperture, the differences in the 
shape of the spire, whorls, é&c., easily and certainly distinguish 
it from R. tridentata. 
