144 NEW YORK ZOOLOGICAL SOCIETY. 
The abdominal cavity contained a considerable quantity of 
thin, yellowish fluid, in which were found several detached cys- 
ticerci without caudal vesicle. 
The examinations were made by putting the cyst upon a slide 
and puncturing it. The hydatid is usually invaginated, but by 
putting it between two slides and exerting slight pressure, the 
head will be protruded, the suckers and hooklets plainly seen, and 
can be counted without staining the specimen. By the addition 
of a little balsam you have a permanent mount. By immersing 
a specimen in 8 per cent. solution of caustic potash, and then 
through a clearing fluid, as oil bergamot, the hooklets are better 
shown. 
