310 Illinois State Laboratory of Natural Htstorij. 



tentacles to the body of the Tokophrya. The nucleus is large 

 and usually oval in shape ; the contractile vacuoles are one 

 to several in number. All the members of this genus repro- 

 duce by internal budding. The young Tohyphrija. is provided 

 ^vith an equatorial circle of cilia, by means of which it swims 

 rapidly through the water, later fastening itself to some 

 object, when the cilia disappear and the form of the adult 

 begins to be assumed. 



METHODS OF CAPTI'KE AND STUDY. 



All of the methods of capture suggested on a later page for 

 the Roti.fera will answer equally well for the Protozoa. Of 

 course, infusions of hay or grass will furnish certain kinds. 

 The method of keeping water from ponds and ditches in 

 watch-glasses as described for the Rotifera, if duly attended 

 to, will not fail to give satisfactory results. Considerable 

 attention should l)e given to the examination of small 

 Crustacea, aquatic insect larvae, pond snails, small turtles, 

 and crayfishes, as many Protozoa are likely to be found upon 

 them. Vorticella may be found on the roots of Lemna, or on 

 fixed aquatic plants. 



Whenever possible, Protozoa should be studied alive. 

 Good results were obtained in the preservation of Tokoplirya 

 quadrijjartita by the following jDrocess. A small colony was 

 transferred to a drop of water upon a slide and a cover- 

 glass placed over it, the cover-glass being raised by little 

 supports of wax so that it did not touch the zooids. A drop 

 of an aqueous solution of corrosive sublimate was then added 

 and allowed to remain about half a minute, when it was 

 washed out aiul 30"'o alcohol substituted, this being grad- 

 ually changed to TO''^. Next, the zooids w^ere stained for 

 about twenty minutes in Kleinenberg's htematoxylin and then 

 decolorized with acidulated alcohol, consisting of .5"^( hydro- 

 chloric acid in 70% alcohol, which in turn was well washed 

 out with pure 10% alcohol. Then the alcohol was gradually 

 changed to 95%, after which clove oil was substituted and 

 allowed to remain until the zooids were clear. Finally they 

 were mounted in balsam. All the changes from water to 



