EXPERIMENTS WITH DAPHNIAS. 211 



to the same conclusion as I did, that the ants perceive 

 the ultra-violet rays with their eyes, and not as suggested 

 by Graber, by the skin generally. It is very gratifying 

 that my experiments and conclusions should thus be 

 entirely confirmed by an observer so careful and so 

 experienced as M. Forel. 



Fig. n^.—Daphnia pulex. a, Antenna?; &, brain; e, eye; h, heart; m, muscle of 

 eye ; n, nerve of eye ; o, ovary ; ol, olfactory organ ; s, stomach ; y, three eggs 

 deposited ia the space between the back and the shell. 



Experiments with Daphnias. 



The late M. Paul Bert made some very interesting 

 experiments on a small fresh-water crustacean belong- 



