1897 - 98 .] Prof. D’Arcy W. Thompson on Marine Faunas. 339 
Boreomysis scyphops, Sars. 
Lophogaster typicus , Sars. 
Stomias boa , Cuv. 
Iialosaurus macrochir , Gunther. 
These are the forms in regard to which the best evidence exists, 
and it is by no means equal or adequate in them all, of specific 
identity between examples from the northern and southern seas. 
In two of them, Pont aster forcipatus and Dy taster exilis, the 
southern form is described as a variety, and in the latter case as 
perhaps a separate species. Differences or doubts are also men- 
tioned in the case of Euplironides depressa, Elpidia glacialis, and 
Stomias boa, and the small Ophiurids probably deserve to be 
re-examined before they bear the weight of a theory. But, setting 
these minor doubts aside, we have in this last list a little assem- 
blage of species that, brought together for one purpose, has at 
the same time another interest of its own. It is framed to 
include the safe and sure residuum of forms common to the North 
Atlantic area and to the southern or Antarctic seas. The species, 
it is true, of which it consists differ much in their known range, 
several going no further south than 35° S. lat., and some having 
a great range in longitude as well as in latitude; and even the 
restricted list contains instances by no means so safe and sure in 
their identification as we would desire. But such as it is, the list 
comprises a collection of deep-water or abyssal species not only 
remarkable for their distribution, but on the whole (apart from its 
Ophiuroids) conspicuous a,s an assemblage of peculiar and aberrant 
forms. I submit that the facts are entirely inadequate to prove, 
even for these species, or for the groups to which they belong, a 
principle of bipolar distribution. They are in the main ancient 
types, the meaning of whose wide distribution has to be studied 
in each case by itself. 
On the Fishes and Isopod Crustacea op the 
Antarctic Fauna. 
I propose, in the next place, to examine the characters of the 
Antarctic fauna as illustrated by the Fishes and the Isopods, with- 
