MORPHOLOGY IN TRICHOMONAS TERMOPSIDIS. 75 



looks as if a single large flagellum proceeded from the body, and, 

 at a short distance, became divided into four. This illusion 

 seems particularly real as one observes the live specimens, but 

 upon careful examination of the stained preparation, it is obvious 

 that the flagella are not only separate outside the cytoplasm, but 

 within it also. The anterior flagella are about three-quarters the 

 length of the body. Specimens stained by Wright's method show 

 the flagella very clearly, and it was not until this technique 

 was employed that the number of flagella was unquestionably 

 established. 



The undulating membrane, (Und. mem., Fig. 2) is a thin, rippling 

 film, apparently composed of a fold of the pellicular covering, 

 attached, at its outer edge, to a posteriorly directed flagellum, 

 which, like the anterior flagella, originates in the centroblepharo- 

 plast. The flagellum separates from the membrane at the pos- 

 terior end of the body, as an inconspicuous trailing flagellum, 

 which is apparently not as well developed as the anterior flagella. 

 The membrane is hyaline, and persists after treatment which 

 dissolves away the cytoplasm of the animal. It is best developed 

 at the anterior end, and becomes less developed and effective 

 tow r ards its posterior end. In preparations stained by Wright's 

 method, the undulating membrane is differentiated into three 

 distinct zones a distal, narrow, pink-staining line, which is 

 probably the flagellum, then a pellucid, unstained zone approxi- 

 mately half the remaining width of the membrane, and lastly a 

 heavily staining (pink) zone which extends to the attachment 

 (Fig. 3, Fig. 6). A similar differentiation was observed in several 

 specimens stained with iron alum haemotoxylin that were more 

 critically decolorized (Fig. 3, D}. 



The chromatic basal rod (Chr. has. r., Fig. 2) extends the length 

 of the body, directly beneath the undulating membrane, in a 

 curve that resembles either a capital "C" or "S." It takes its 

 origin from the centroblepharoplast, and like that organelle, 

 stains intensely black. It retains its stain, ordinarily, 'after the 

 nucleus has become quite decolorized. Whether it functions as 

 a source of energy for the motor activities of the undulating 

 membrane (Kofoid and Swezy, '15) or serves as a skeletal support 

 for that organelle, the fact is that the membrane seems to be 



