THE DISTRIBUTION OF TERRESTRIAL CRUSTACEA. 155 
appears even more hopeless. Most of the freshwater crustacea, 
such as Daphnia, Cyclops, &c., lay eggs which may be dried, and 
thus blown by the wind to great distances, or they may adhere 
to the feet of aquatic birds, and by this means be carried from one 
place to another. None of these means of dispersal, however, 
can be of any use with the terrestrial Isopoda. They live in 
places very similar to those inhabited by land shells—that is to 
say, in damp situations under dead leaves, sticks, &c.; some 
species being found in open country, others only in the bush. 
They have no great powers of locomotion, for they are small, and 
can only creep from one place to another. They cannot live in 
water, and though they lay eggs, they carry them about in an 
incubatory pouch under the body until the young, which at birth 
usually resemble the adult animals, are hatched. This is, at least, 
given as the general rule. I know that it is the case with Por- 
cellio graniger, Oniscus punctatus, and Philougria rosea. Wence 
it would appear that arms of the sea, snow covered ranges of 
mountains, or even large rivers, would be barriers which could 
only be crossed by occasional lucky accidents. It is, indeed, a 
matter of surprise that they should be so widely distributed in 
the same country. orcellio graniger, for instance, appears to be 
found in all parts of New Zealand. Onzscus punctatus is found 
at Dunedin, and is also widely distributed’ in Canterbury, and 
Philougria rosea 1 have taken in several widely separated situa- 
tions in Canterbury. Probably floods are the means of aiding 
in their dispersal to a certain extent, and I can give what appears 
to be an example of this. Cudaris rugulosus is a species which 
‘seems to be common in the bush in some parts of Canterbury. 
I have taken it both at East Oxtord and at View Hill. I have 
never seen it outside the bush, except in one place at Eyreton, 
and this was under some river-bed logs that had been brought 
from the Waimakariri for firewood. In the bush it is often found 
on the under surface of logs, and I think some living specimens 
must have been adhering to some of these logs on the banks of 
the river, and thus got washed down during a flood. The logs 
have now all been burnt, and the little colony appears to have 
died out, for I did not succeed in finding any when I searched a 
short time ago. Possibly in the same manner terrestrial Isopoda . 
may sometimes be carried across the sea, but this would, I fancy, 
very rarely happen. I have not made any experiments, but I 
imagine they very soon die in sea-water—they do not live long 
in fresh water—and it would only be by creeping into some cre- 
vice in the upper part of the log that they could escape from the 
salt water. Want of food would be another difficulty, for as they 
always seem active, I don’t suppose that they could live for very 
long without food, as some land shells do. 
In Mier’s “ Catalogue of the Stalk and Sessile-eyed Crusta- 
cea of New Zealand,” nine terrestrial species of Isopoda are put 
down to New Zealand. Of these I know only Armadillo specio- 
sus, Cubaris rugulosus, and Porcellio graniger. Since the publi- 
cation of the Catalogue, Mr. G. M. Thomson has added Oxzscus 
