496 MURICIDAL. 
colour is pale yellowish-white, shot with slight hues of red, 
~ and the flakes are snow-white. These differences are cer- 
tainly not very important, but they do not appear to de- 
pend on food and habitat, and they are constant in the 
two species; I am therefore rather inclined to think that 
there may be sufficient grounds for specific distinction. There 
is no trace of operculum, and in other respects they closely 
agree with the type, except that here the pleurotomic sinus is 
very inconsiderable. This is the var. /evigata, ‘ Brit. Moll? 
vol. iii. p. 478 :—figs. 8, 9 of pl. 114 are this form and our 
M. nebula. 
A further examination of the M. Ginannianus and M. nebula 
induces us to consider them distinct; and as far as a shell 
examination is available, we think the large var. pyramidata 
of the ‘Brit. Moll.’ is also distinct. There is no figure of 
this form; it is twice the size of either of the other varieties, 
and is as rare as the others are common. 
M. pracuystoma, Philippi. 
Mangelia brachystoma, Brit. Moll. iii. p. 480, pl. 114. f. 5, 6; (animal) 
pl. R.R. f. 2. 
The Pleurotoma brachystomum of Philippi, recorded in the 
2nd vol. p. 169 of the ‘Enumeratio Moll. Siciliz,’ appears to 
be distinct from M. Ginannianus, judging from the characters 
of the shells, which exhibit greater distinctive marks than the 
animals. We have examined the two alive, and the only per- 
ceptible difference is in the colour, which in this species is 
pure hyaline, without the least effusion of the pale red or 
yellow-brown which is apparent in M. Ginannianus ; and the 
snow-white flakes on the upper part of the foot are very 
distinct, and do not run into each other as in its congener. 
At Exmouth the two are taken together in the coralline 
zone. The M. Ginannianus also occurs commonly in the 
laminarian zone in company with M. nebula, but in that 
habitat we never met with the MW. brachystoma. It must be 
admitted that the specific distinctions between these species 
are even less important than those between WM. Ginannianus 
and M. nebula; the shells exhibit some distinctive characters, 
