210 Dr A. Philippi on the Recent and Fossil Mollusca of the 
of Aspergillum maniculatum, Perna Soldanii, Plicatula my- 
tilina, Strombus coronatus, Terebra fusca and duplicata, Vo- 
luta rarispina, and Ancillaria obsoleta, is at first sight in 
favour of a warmer climate, because these genera do not 
occur in the seas of the northern temperate zone ; and it 
cannot be denied that the species most closely allied to Cytherea 
multilamellosa is Cytherea cygnus, which now lives near Can- 
ton (not in the Mediterranean, as conjectured by Deshayes). 
The number, however, of living and extinct species which 
favour the idea of a warmer climate, is extremely inconsider- 
able, in comparison to the number of the remaining species ; 
and we have, on the other hand, species which are now con- 
fined to colder seas, such as Mya truncata, Cyprina islandica, 
and Fusus contrarius ; so that we are entitled to regard it 
as an incontrovertible fact, that, in Southern Italy, at the time 
of the Tertiary period, the climate was neither much warmer 
nor much colder, than it is at present. It can hardly be urged 
as a valid argument against this view, that simultaneously, 
vr at a later period (we shall afterwards see that the palzeon- 
tological phenomena admit of no separation of the Tertiary 
period, from the Diluvial period, and from the Alluvial period). 
Elephants, Rhinoceroses, and Hippopotami, also lived in 
Sicily, because these animals, belonging to different species 
from those which now live in hot climates, could exist per- 
fectly well in the present climate of Sicily. 
III. Physiognomy of the Mollusca of the Tertiary Period and 
of the present day. 
If we consider the relative abundance of the species from 
which results what may be termed the Physiognomy of the 
molluscous fauna, we find not a few species equally common 
at the present day and in the Tertiary period ; but also that 
a number of species formerly very abundant, have become 
rare or even extinct, and vice versa, a number of species are 
now very abundant which were formerly rare or altogether 
awanting.* Itmay be remarked, that the very species which 
* We regret that want of space prevents us from giving Dr Philippi’s 
lists illustrative of this part of the subject, and that the same reason 
will oblige us to omit the detailed lists under Sect. IV. of the present 
memoir.—EDI1rT. 
