24 Gollhegie of Fone sitry 
tum as to number of layers, the amount and arrangement of the con- 
nective tissue, etc. His account of the parts of the cyst apply to these 
small cysts both as to general appearance and as to structural detail. 
I have thus far found it very difficult to get the fixing fluids to pene- 
trate this cyst and when I have attempted to remove the cyst, the 
worm has been greatly distorted and torn. These cysts are not all of 
the same age, for part of them are oval with a blunt process on one or 
each end that is in contact with the muscle. These younger cysts 
do not have the walls of the cyst well developed as the stain will 
penetrate as it will not in the older ones. JI have not been able to 
section the latter in paraffin because the alcohol and clearing oil as well 
as the paraffin did not penetrate. So far as I have been able to 
determine with the limited amount of material at my disposal, two 
distinct stages are represented. In the older cysts, the young worms 
Original by W. M. Smallwood 
Ficure 10. One of the smallest and youngest of the cysts found in 
the muscles of the perch. There are four round bodies which take 
a deep stain but the cells are not as yet organized into definite organs. 
8 mm. long, .6 mm. wide. Original. 
have a well developed oral sucker, digestive and reproductive organs. 
I have not been able to homologize all of the structures with those in 
the adult due to unsatisfactory sections but so far as I have gone the 
results indicate that this is a young stage of the adult. The younger 
cysts are filled with a mass of loose cells and connective tissue contain- 
ing from one to three distinct round bodies. These round bodies take 
a deeper stain and vary much in size. Each is surrounded by a con- 
centrically arranged layer of connective tissue. So far as has been 
