166 PROCEEDINGS OF THE MALACOLOGICAL SOCIETY. 
Margarita, besides occurring in the north Atlantic and the Southern 
Ocean, has also been found in the Indian Ocean, likewise the Dentaliwm 
and Puncturella are both so widely distributed that their occurrence 
in deep water in intra-tropical latitudes is very probable. 
Hence I think that in reality there is practically no identity between 
the northern and southern molluscan faunas. Moreover, putting aside 
specific identity, we do not discover any similarity from a generic 
point of view, for not one of the eleven genera quoted has a limited 
distribution; on the contrary, with the exception of Glomus and 
Homalogyra, of which we know comparatively little, all have practically 
a worldwide range. 
In conclusion, I would also point out that I do not find any peculiar 
specific or generic identity in the published lists of Arctic and 
Antarctic Mollusca. Certain genera are usually considered boreal 
types, such as 
Admete. Yoldia. 
Lrichotropis. Cyprina. 
Bela. _ Artarte. 
Velutina. Lyonsia. 
Lamellaria. Mya. 
Buccinum. Cyrtodaria. 
Trophon. Saxicava, ete. 
Liomesus. 
Now it is a suggestive fact that not one of these genera is exclusively 
restricted to the two regions under discussion. One or two are solely 
Arctic, and the rest, although having both northern and southern 
representatives, also occur at intermediate stations or have a con- 
siderably wide distribution. 
On the other hand, it may be shown that certain Antarctic genera 
are restricted to that region and do not occur in the north, although 
met with in other parts of the world. Among these may be cited 
Euthria, Bullia, Photinula, Siphonaria, Ranella, Acanthina, Voluta, 
Struthiolaria, Cominella, and Modiolarca. 
It is a notorious fact that Mollusca from high latitudes and from 
deep water are to a great extent devoid of bright colours. Even this 
prevailing dull appearance of the shells from the Arctic and Antarctic 
areas is almost enough to suggest an imaginary resemblance. 
Although much might be written upon this subject, indeed the 
discussion might be prolonged to any extent, I think enough has 
been said to show the fallacy of this bipolar theory, at all events from 
a mollusean point of view. 
Nevertheless, Dr. Pfeffer, referring to the examination of collections 
received from Patagonia, observes—‘‘ One thing can be affirmed with 
decision, that the theory of the great similarity of the faunas of 
higher northern and southern latitudes receives new support from the 
working out of nearly all groups; and the accord between the two 
faunas extends to hundreds of genera.” 
Perhaps some day he will publish a list of these forms. We shall 
then be in a position to judge to what extent these hundreds of genera 
are bipolar. 
