X APPARATUS AND MATERIAL 



besides, renders the object more transparent. None of the animals 

 studied here need to be stained and mounted in balsam or other per- 

 manent medium. In the case, however, of the tapeworm, the hydroids, 

 and perhaps one or two of the other forms, the animal can be studied 

 with greater profit if thus stained and mounted, and it is recommended 

 that the student be provided with such specimens. 



As a rule the material needed can be easily obtained. Most of the 

 animals studied as well as microscopic preparations may be purchased 

 from the supply department of the Marine Biological Laboratory at 

 Woods Hole, Massachusetts ; General Biological Supply House, 761- 

 763 East 69th Place, Chicago; New York Biological Supply Co., 

 34 Union Square, New York ; Michigan Biological Co., 324 South 

 State Street, Ann Arbor, Michigan; H. Edward Hubert, 3615 Mel- 

 pomene Street, New Orleans ; Southern Biological Supply Co., Natu- 

 ral History Building, New Orleans; Pacific Biological Laboratory, 

 Pacific Grove, Washington ; or other dealers in such suppHes. Powers 

 & Powers, Station A, Lincoln, Nebraska, will furnish live protozoans 

 and hydras, also microscopic slides of these animals. 



