MEDUSA AS HOSTS FOR LARVAL TREMATODES. 59 
adult form. The body in this stage, however, is crowded with gland cells 
along the sides reaching from the pharynx to well behind the ventral 
sucker. The pigment spots anteriorly are very well developed. The 
excretory vesicle is long and narrow, just as Nicoll describes it, its ducts 
in the larval form showing particularly clearly. At the hind end is%a 
strong sphincter guarding the opening posteriorly ; in front of this the 
main excretory branches are given off which send one branch backwards 
and a much convoluted branch forwards. The flame cells are particularly 
well seen in the living larval forms. As Nicoll’s description does not enter 
into the details of the excretory system a figure of the larva is given, 
showing the main points. 
REFERENCE. 
1910. Nuiconn.—On the Entozoa of Fishes from the Firth of Clyde. 
Parasitology, Vol. III, No. 3. 
