496 MUKICID^E. 



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. l&vigata, ' Brit. Moll/ 

 vol. iii. p. 478 : figs. 8, 9 of pi. 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. BRACHYSTOMA, Philippi. 



Mangelia brackystoma, Brit. Moll. iii. p. 480, pi. 114. f. 5, 6 ; (animal) 

 pi. R.R. f. 2. 



The Pleurotoma brachystomum of Philippi, recorded in the 

 2nd vol. p. 169 of the 'Enumeratio Moll. Sicilise/ 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 M. brachystoma. It must be 

 admitted that the specific distinctions between these species 

 are even less important than those between M. Ginannianus 

 and M. nebula ; the shells exhibit some distinctive characters, 



