55 
These species, or rather presumed species, appear to be varieties 
of the same kind, peculiar to certain districts of the Indian Ocean. 
If we select certain specimens of each, they appear very distinct; 
but if a large number of specimens of different ages, from various 
localities, are arranged together, the differences gradually merge 
into each other, and it is difficult, if not impossible, to separate 
them from one another. In the younger specimens the spines are 
generally distinct and crowded; sometimes they enlarge more rapidly 
than the rest of the shell as it increases in size ; in other specimens, 
after a time they suddenly cease to be developed, and the larger 
external whorls are not armed behind. 
+tt Spire exposed, convex, large, crowned with numerous small, 
rather inflexed spines. 
8. Cymsrum Bropertpi, Gray. Japan Melon. 
White, with chestnut lines or spots; young shell concentrically 
sulcated ; hinder part of the whorls near suture crenulate. 
Melo Broderipii, Gray, G. A. K. 1833. 
Melo regius, Brod. 1855. 
Hab. Manilla. Japan, Humphreys. 
+ttt Spire produced, conic, armed with compressed inflexed scales. 
9. Cympium Mitrtonis. 
Melo Miltonis, Gray, G. A. K. t. 29, 1833. 
Melo cylindratus, Brod. 1855. 
Hab. Australia; Swan River. 
b. Shell ovate or fusiform, covered with a thin periostraca ; aper- 
ture moderate. 
§ Pillar with four or five strong well-defined plaits. Operculum 
none. Foot moderate. 
3. ScAPHA. 
Shell ovate or fusiform. Periostraca thin, smooth. Spire conic ; 
aperture moderate; inner lip smooth, defined, pillar 5- or 6-plaited. 
Operculum none. 
+ Nucleus or shell of the very young animal very large, irregularly 
spiral. 
1. ScaPHA MAMILLA. 
Nucleus very large, subglobose, apex of spire lateral. 
Voluta mamilla, Gray, Sow. Conch. Thes. 207. t. 50). £57,558; 
Cymbium mamilla, Adams, 159. 
Hab. Australia ; Van Diemen’s Land. 
2. ScaPHA DUBIA. 
Nucleus large, rather irregular-shaped, spiral apex acute. 
Voluta dubia, Brod., Zool. Journ. iii. 81. t. 3. f.1; Sow. Conch. 
Thes. 209. t. 55. f. 115. 
Fulguraria (Aurinia) dubia, Adams, 166. 
Hab. ? Cab. Roussel. 
