16 University of California Publications in Zoology [Vol. 2o 



SUMMARY 



1. Streblomastix strix occurs as an intestinal parasite of the ter- 

 mite Tcrmopsis angusticollis and is usually found attached to the 

 epitheliiim of the intestine posterior to the malpigliian tubules, seg- 

 regated from the other parasites in the lumen. 



2. It is a linear organism ^vith the nucleus elongated to conform 

 to the shape of the body. Its neuromotor apparatus consists of 

 centrosome, blepharoplast, four myonemes and six flagella, connected 

 with the nucleus by the rhizoplast. 



3. Binary fission aj^pareutly occurs without spindle formation. 

 The nucleus elongates and becomes constricted prior to the con- 

 striction of the protoplasmic body. 



4. Multiple fission is a cj'clie process occurring in many individuals 

 in a single host at one time. It may be preceded by the formation of 

 giant individuals. The body retains its linear formation throughout 

 the process as in binary fission. The nucleus elongates and constricts 

 into daughter nuclei. The greatest number observed is eight. 



5. The shape of the body and the arrangement of its neuromotor 

 apparatus show striking adaptation to the habitat in which the flagel- 

 late is found and to its parasitic mode of life. 



6. Strehloma-stix forms a living link between the Polymastigina 

 and the Triehonymphidae but without close relations in either group. 

 We therefore propose for it a new family, Streblomastigidae, which 

 we place in the Polymastigina. 



Zoological Laboratory, University of California, 

 Berkeley, California. 

 Transmitted Septeniier 5, J918. 



