1919] Kofoid-Swezy: Trichomitus termitidis 23 



that is seasonal in its occurrence, as shown by examinations of the 

 host which have been made throughout the year. 



Trichomitus greatly resembles its near relative Trichomonas in its 

 activities. It is, however, difficult to keep these flagellates alive in 

 cultures, hence observations on the active forms have been limited. 

 The extreme fragility of the cytoplasmic body as contrasted with the 

 stout, persistent parabasal body, is particularly striking in prepara- 

 tions of living material. A few seconds usually suffices, in ordinary 

 tap water, for the dissolution of the protoplasm, leaving the neuro- 

 motor system still intact. 



Nutrition in Trichomitus is holozoic. It, like Trichonympha, is 

 evidently only a commensal, or at least is not truly parasitic, i.e., liv- 

 ing on the tissues or fluids of the host. The food particles found 

 within the cytoplasm consist principally of wood}^ fibers upon which 

 the termite feeds. 



MORPHOLOGY 



The morphology of this species of Trichomitus is of especial signifi- 

 cance not only in view of the distinctness with which the neuromotor 

 organ system is developed and integrated but also in the unquestion- 

 able certainty with which the relationship of the centrosome to the 

 blepharoplast is established, as will be shown later. The relatively 

 large size of the organisms (75 to 150/x) and their abundance have 

 made possible an analysis of these structures not obtainable with the 

 smaller trichomonads of our earlier studies (Kofoid and Swezy, 1915). 



Sh.\pe and Size op Body 



The body of Trichomitus termitidis is exceedingly amoeboid and 

 protean in life, having neither constancy of form nor resistance to 

 deformation on contact with other organisms or objects. Its periplast 

 is unusually thin and delicate and in the larger forms especially is not 

 infrequently ruptured in the making of smear preparations. It has 

 nevertheless a certain characteristic range of forms within which, in 

 free movement, it is seen or preserved on fixation. These vary from 

 the asj'mmetrical pyriform contour, with the large end anterior and 

 the posterior tapering to a blind point (pi. 3, fig. 1), to the ellipsoidal 

 (pi. 3, fig. 14) or subspheroidal shape (pi. 3, fig. 5), with the slightly 

 greater diameter posterior to the center. 



