THE TREMATODA 



lets, [but without suckers. The larva possess four eyes, an intestine, 

 and a well-developed excretory system. During its passage through 

 the water, the larva seeks for a young tadpole of the frog, and not 



Fio. IV. 



finding one within twenty-four hours, the cilia degenerate and the 

 animal dies. But having come across its future host, it swims and 

 creeps leech-like over the surface of the body till it arrives at the 

 branchial aperture; into which it darts with great suddenness. 



