92 
TEKKESTKIAL MOLLUSCA IxNlIAKlTING SOCIETY ISLAxVDS. 
Jiaimodonla, conica^ Martens and Langk., Don. liisni., p. 57, I 1. HI, fljj* 13. 
IHecotrema Anaaensis, Paetel, Cat. Conch., p. 114. 
Melampus conic us, Pfeiffer, Mon. Pneiira., iv (Aui'iculacea)^ p. 319. 
? Melampus Anaaensis, Pfeiffer, 1. c., p. 320. 
This spocics, though ranging from the Paumotu to the Viti Islands, is rarely found 
in the Society group. It is smaller and not so robust as L. Bronni of the Sandwich 
Isles. The spiral impressed lines are more conspicuous, and the aperture exhibits a 
heavier deposit of callus in the palate. 
Genus PLECOTREMA, H. and A. Adams. 
P. MORD.iX, Dolirn. 
Plecotrema mordax, Dolirn, Mai. Blat., 1859, p. 204. Pease, Jour, de Conch., 1871, p. 93. 
Martens and Langk., Don. Bisra., p. 55, PI. Ill, fig. 8. Paetel, Cat. Conch., p. 114. 
A few dead specimens found on the seashore on the northeast coast of Tahiti. It 
is not uncommon on the Paumotu Isis. 
The examples now before me are more globose than any Polyne.sian species known 
to me. 1 he riblets are rounded and rugose. My specimens average from 5 to 6 
mdl. in length, and are nearly white with a very broad, light fulvous zone. 
Genus DIADEMA, Pease. 
Amer. .Tour. Conch., 1868, p. 158. 
Oarrettia, O. Semper, Cat. Mus. Godeff., v, p. 100, 1874. 
D. IIIANOULATA, Pease. Plato II, fig. 29. 
Crjcloxtoma hiangulala, Pease, Proc. Zool. Soe., 1864, p. 674. 
Genus OMPHALOTROPIS, Pfeiffer. 
globose-turbinate to elongate-conical. 
author for the reception of a group of 
r the filiform carina which circumscribes 
ed peristome, and in shape varying from 
