Xll APPARATUS AND MATERIAL 



medium for making temporary mounts of most of the objects 

 examined under the microscope. A solution made of equal parts 

 of water and glycerine, however, is usually preferable to water, as 

 it will not dry up and, besides, renders the object more transparent. 

 None of the animals studied here need to be stained and mounted 

 in balsam or other permanent 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 may be purchased from the supply department 

 of the Marine Biological Laboratory at Woods Hole, Mass. ; F. D. 

 Lambert, Tufts College, Mass. ; H. M. Stephens, Carlisle, Pa. ; or 

 other dealers in such supplies. Blackford's, Fulton Market, New 

 York City, will furnish the crayfish, the lobster, the edible crab, 

 the French snail (Helix pomatia), and the squid. Powers & Powers, 

 Station A, Lincoln, Neb., will furnish live protozoans and hydras. 



