ISOPODA. 3 
it would have been more appropriate to make the provinces coincide with the oceans to 
the north. It may be so, but it seems to me to name the provinces from the point 
of attack is the wisest course in the present state of our knowledge. The more I see 
of the South Polar fauna the more certain I become that a very large proportion of 
species have a circumpolar distribution. It would also appear that the northwardly 
projecting spur of Graham’s Land, which passes for some considerable distance beyond 
the Antarctic circle, constitutes a barrier round which species have a difticulty in 
passing. Whether the South Polar fauna originated in those latitudes and has spread 
northwards, or whether it has acquired its present aspect by migration from the north, 
is a speculation which will be material for discussion for many years to come. Be this 
as it may, our greatest knowledge will lie nearest to the three points of attack, and 
from these it will be comparatively simple to investigate the passage of various species 
northwards into the great oceans. A circumpolar fauna will specialise more or less 
distinctly as it passes northwards, and its ancestors or other relations become separated 
by the great land masses. Or, if investigation shows the migration to be in a southerly 
direction, we have in those oceans three independent streets down which the fauna 
passes to mix beyond their junctions, or to pass on to the uttermost limit where 
uniform conditions, within certain limits, must have their effect. 
The collection brought back by the ‘ Frangais’ from the west coast of Graham's 
Land is very like that of the ‘Discovery,’ no less than eight species are common to 
both, their total number being thirteen. 
The collection of the ‘ Scotia’ is still in my hands for description, the shallow 
water and littoral forms come from a more northerly latitude, the South Orkneys, the 
deep sea forms from the Weddell Sea. I can only say here that this collection does not 
contain a single species taken by the ‘Discovery.’ Three other Antarctic collections 
remain to be described ; how far they will bear out the opinion expressed above remains 
to be seen. 
Antarctic. Sub-Antarctic. 
Apseudes antarctica Beddard 
45 spectabilis Studer 
Tanais willemoesi Studer 4 
»  hirsutus Beddard : : 
Typhlotanais kerguelenensis Beddar 
Leptognathia australis Beddard 
Nototanais dimorphus Beddard : 
9 antarcticus Hodgson. : ; : : ‘ x 
Paranthura neglecta Beddard : , F : 
* Leptanthura glacialis . : : : : : ‘ , x 
* Gnathia antarctica Studer. ‘ 4 : : : ; x x 
,,  tuberculosa Beddard ‘ ‘ 3 , ‘ ; x 
* Buneognathia gigas Beddard : ; ; : , : x x 
Aiga magnifica Dana. ‘ : f ' : F : x 
x 
x 
x 
xXXXXXX 
* 
x 
5, semicarinata Miers 
» punctulata Miers 
», edwardsi Dollfus . 
