100 University of California Publications in Zoology [Vol. 20 



INTRODUCTION 



In our previous studies on the parasites of the termite, Termopsis 

 angusticoUis Walker, we have described three of the curious and 

 highly interesting protozoans in this faunal complex. These are 

 the flagellates Streblomastix strix (1919a), Trichomitus termitidis 

 (1919&), and Trichanympha campanula (1919c). A fourth member 

 of this group remains to be noticed. This flagellate is closely akin 

 to Trichonympha campanula yet presents some striking differences 

 which, in our opinion, give it a position genericallj^ distinct from that 

 species. We therefore propose for it the name Leidyopsis sphaerica 

 gen. nov., sp. nov., naming it in honor of the pioneer investigator of 

 this group, the American naturalist Dr. Joseph Leidy. 



It is less abundant than are the other members of this association 

 of termite parasites. It is found in the lumen of the intestinal tract 

 and is in no case attached to the walls. In this location, as also in 

 its activities, it resembles Trichonympha campanula. The mass of 

 flagella attached to the anterior portion of the body stream backward, 

 partly clothing its rotundity. In the living animal the action of the 

 flagella is similar to that of its larger relative. Waves of contraction 

 pass from the proximal to the distal ends of the flagella without 

 cessation. Owing to the differences in the shape of the body its 

 anterior end is slightly less mobile than is the case in Trichonympha 

 campanula. Its rate of progression is also somewhat slower, as though 

 impeded by the rotundity of the body in moving through the seething 

 mass of organisms found in the intestinal tract. 



MORPHOLOGY 



In its morphology Leidyopsis presents a type of structure which 

 is as highl}^ differentiated as that found in Trichonympha. It differs 

 from it mainly in the extent and distribution of the specialized struc- 

 tures as compared with the remainder of the body. These differences 

 will be pointed out more specifically below. 



The outstanding feature of its morphology, next to its abundant 

 supply of flagella, is its neuromotor system, which is of the tricho- 

 n^Tuphid type (Kofoid and Swezy, 1918c). Correlated with this 

 are the ectoplasmic differentiations, while the remainder of the body 

 presents no structural features which mark an advance over that of 

 the simpler flagellates. The evolutionary development of organelles 



