134 TlMEHRI. 
prevent light reaching it. It has, however, the funda- 
mental stru6ture of an eye, being supplied with a median 
nerve from the brain, and this nerve is distributed to 
form an apparently sensitive visual area. The arrange- 
ment of the layers in this visual area, is, however, 
on the plan not of the ordinary eyes of the vertebrate 
animals, but of the eyes of the inverbetrates, such as the 
snails, cuttle-fishes, etc. This is an extremely important 
and interesting fa6l, since one of the lowest allies of the 
vertebrates, the Ascidians, a group once classed close to 
the snails and cuttle-fishes, possess in early life a single, 
median eye imbedded deeply in transparent flesh where 
light can reach it. This parietal eye of Iguana, from 
its position and stru6lure, thus seems to be a survival 
from a primitive condition. In development, it arises as 
a small outgrowth from the roof of the brain. The out- 
growth becomes constricted, the upper part to form the 
" eye", the connecting part the nerve. A parietal eye 
has lately been discovered in fishes, and doubtless impor- 
tant additions will soon be made to our knowledge by the 
researches of Beard who is investigating the matter. 
A profitable Sugar-palni. — The following passage 
from WALLACE'S " Tropical Nature " seems worthy of 
more than a passing notice — particularly at this time when 
every possible attempt is being made to lessen the cost 
of sugar produ6lion from the sugar cane, often by means 
of experiments entailing very considerable expense. It 
seems a good opportunity for some of our wealthy capit- 
