34 The genus Apus in Baluchistan. { March, 1905. 
cannot say for certain that this one was not of that kind, but 
from its appearance, this seemed unlikely. On approaching the 
pool I found it swarming with the crustacea of which I here give 
e ske is roximately of natural size. 
nite diagrammatic, but saliteiently detailed to enable clear identi- 
fication of the o ject ee eG The diagram sag seagria: 7 
Boy extending beyond the shield is te eepniltaly longer than 
in the specimens and figures that have been shown to me b 
Major Alcock and Mr. Annandale. Its relative dimension is pos- 
sibly slightly exaggerated in my sketch. There is no doubt, how- 
pair of eyes in the anterior part of the shield. There exists, 
Apus, a third unpaired eye placed slightly further bag than the 
line joining the paired eyes, but it is very small and easily escapes 
detection if one does not know of its existence. The candal 
appendages are much shorter in my sketch than in the figures and 
vary which I have seen in Calcutta. Perhaps they had got 
broken in my specimen. 
e presence of so large a number of crustacea in the situa- 
tion where I observed them, appears very puzzling. If the pool 
was the remnant of a larger pond temporarily filled by rain-water, 
one can understand that they should have gradually become 
crowded into a small space as the water receded, but their deve- 
lopment must have been very rapid, for if the l is not one of 
the perennial ones alluded to, it could scarcely have existed for 
more than two months previous. If the pool is perennial and: 
normally of the small size it Studs ate when I saw it, its crowded 
population is still difficult to a A 
As noticed at a previous ‘iting <é Mr. oe it is prob- 
able that the reputed absence from this country of many well- 
known fresh-water invertebrates is this to our scant knowledge of 
its poral fauna. 
r. Annandale has maggots my attention to the account of the genus in 
bint tices History of the British mother ce cording to which 
Apus can reach a length of oneinch after three weeks d seats pment from the 
egg. It has also been noticed in Europe that sg crustacean appears sporadi~ 
cally and suddenly in an unaccountable mann | 
