1919] Kofoid-Swczij: Strcblomastix stric 3 



papers. lu the present paper the foiirtli member of this group, also 

 a polymastigote flagellate, will be considered, with a discussion of its 

 morphology, relationships and life history in so far as they have been 

 determined. 



Technique 



The flagellates found in the termites are exceedingly delicate. 

 Great difificulty has been experienced in keeping them alive for con- 

 tinuous observation under the microscope for any length of time. 

 The use of distilled or tap water resulted in the complete dissolution 

 of the larger flagellates in a few minntes. The smaller ones would 

 survive a somewhat longer period, ^^arious other culture media were 

 tried, such as Ringers' solution, normal salt solution, malted milk and 

 the white of egg. Of these the last one was the most successful, a few 

 flagellates surviving in the culture at the end of twenty-four hours. 

 These cultures were made with a lianging drop or with a greater 

 amount of fluid in a deep culture slide. 



Intra vitam stains, such as neutral red, Janus green and new 

 methylene blue 6 6, were used. Of these neutral red gave the best 

 results. 



The methods of fixing and staining which have been found the most 

 satisfactory were those outlined by us in previous work on parasitic 

 flagellates (Kofoid and Swezy, 1915), that is, a modifled Ileidenhain's 

 iron haematoxylin following fixation in hot Sehaudinn's flmd. Other 

 stains as well as various fixing agents were tried, both with smear 

 preparations and with sectioned material. In the latter cases two 

 methods were followed. In the first the entire abdomen of the termite 

 was used, fixed in Sehaudinn's or strong Flemraing's solution. In the 

 second the intestine was teased out in a drop of normal salt solution 

 and then placed in the fixing fluid. These sections were stained with 

 haematoxylin or with a modified JIallory's connective tissue stain 

 (Yocom, 1918). 



Considerable difficulty has been experienced in making good prepa- 

 rations of this material by the ordinary smear methods. The exceed- 

 ing delicacy of the various flagellates I'esults in distortions of the body 

 and breaking down of its cytoplasmic organization. This is usually 

 confined to the posterior end, leaving the anterior end, nucleus and 

 motor organelles intact. This difficulty was partly overcome by using 

 albumen fixative on the cover slip and diluting the contents of the 



