EXPERIMENT STATION BULLETINS. 



429 



polymorphism in the hfe cycle. Some of these may be transitional forms 

 and others may be merged upon further study. 



Types 1 and 2 are shown in Fig. 3, and another individual of type 1 more 

 highly magnified is seen in Fig. 4. The flagella may project in the axial line 

 from the body of the organism or they may emerge slightly to one side of the 

 axial line. The flagella extend into the body of the organism for a very short 

 distance and seem to have their origin in blepharoplasts or basal granules 

 which are located near the extreme ends of the flagellate. These basal 



Fig. 3. Photomicrograph of biflagellate, elongated protozoaii in sieve tube of mosaic bean plant 

 X 1500. 



A. Elongated organism of tjrpe 1. 



B. Flagellum. 



C. Ovaliform flagellate, type 2. 



D. Cell nucleus with deeply-stained nucleolus in center. 



granules take the stain more intensely than the rest of the organism and are 

 easily located. 



The nucleus is apparently little affected by the haematoxylin stain, 

 although an occasional one, faintly colored, is seen centrally located in the 

 cell. Special stains will have to be used to bring out details of structure. 

 So far the polychrome methylene-blue stains and their modifications have 

 not given satisfactory results with plant material. The main difficulty seems 

 to be that destaining or dehydration in alcohol removes the stain from the 

 organisms as well as from plant structures. 



The majority of these flagellates lie in a plane parallel to the long axis of 



