224 NOTE BY J. B. INGPEN. 



and open cell which had been introduced by Mr. W. P. Mar- 

 shall so long ago as 1869, and which he thought, like the 

 apparatus just described, had fallen into unmerited disuse. It 

 was simply a cell, of any required dimensions, cemented to a 

 glass slip, and only half coyered with thin glass. When inclined 

 it could be used as a zoophyte trough ; when laid flat half of it 

 was an open cell, the wall around it preventing the escape of 

 objects or fluid, so that dissections could be made or objects 

 arranged and returned into the covered half for examination. 

 Mr. Marshall's paper is reprinted in the " Monthly Microsco- 

 pical Journal," Vol. i. (1869), p. 239. 



In answer to a question, Mr. Ingpen said that he had no 

 difficulty in cleaning the troughs with a curved stick or wire, 

 or a long camel's-hair pencil, or, for the shallower cells, a piece 

 of folded paper, wetted with water or alcohol. 



