250 



H. J. FASE, DESCRIPTION OF A ZOOPHYTE TROUGH. 



ring B, the cover D pushed in as far as found desirable, and water 

 added if required, by the opening or slot F, which may be closed 

 by a plug of cotton wool as before. 



The advantages of the above-described apparatus are, that it 

 admits of the easy arrangement of the object to be examined. That 

 it is readily cleaned. That as no metal is used in its construction, it 

 allows of prolonged observations being carried on without disturb- 

 ance of the object. That water, either fresh or salt, may be added 

 from time to time, and that the thin cover-glass permits of high 

 powers being used, and is readily replaced when broken. 



F / O. A 



