8 
insects are marvellously adapted either to short or long vision. 
Compound eyes differ enormously in the number of their parts, 
in the ant, there are but 50, in the house-fly they number 8,000, 
while in the dragon-fly, some 12,000 have been counted. The 
eye of the Cephalopod approaches nearer to that of the Verte- 
brates. In the cuttle-fish the curious fact is noted that the 
retina is behind the choroid. 
The eyes of all Vertebrates are of the same type, though with 
interesting modifications. That of the fish with its large socket 
and cushion of soft tissue, its flat cornea and close approxima- 
tion of the retina to the lens shews how admirably? it is adapted 
to the medium which surrounds it, and to the conditions under 
which the fish exists. 
Mr. Rean then touched on many interesting facts connected 
with the eyes of Amphibia and Reptilia. He also called attention 
to the eyes of some birds, and remarked on the great difference 
which exists between those adapted to long vision in brilliant 
sunlight as the eagle’s, and those of birds flying at night as the 
owl’s. 
Another wonderful instance may be observed in the eye of 
the mole, with all the curious modifications of structure which fit 
it for the abnormal conditions under which the animal lives. 
NOVEMBER, 30th, 1887. 
—_——~->——_ 
MICROSCOPICAL MEETING. 
subject’ “Ev Es.” 
Introduced by Mr. W. H. REAN. 
