lf'l<;i t<irfvi: KuKtoiiHclfus of FluficUalrs 227 



the kiuetouucleus of Trypanoplasma, the chromidial body of Bodo, 

 both of which have already been discussed here, and the chromidial 

 body of Monocercomonas bufonis Dobell. In regard to the latter species 

 there is a strong probability that it and the form described above as 

 Polymastix bufonis are one and the same form. A further discussion 

 of this will, however, be given in a later communication. 



These facts show that a comparison of the parabasal bodies of the 

 Trichonymphida, the chromatic basal rod of Trichomonas, the chro- 

 midial bodies of Polymastix and Prowazckia, and the "kinetonuclei" 

 of the haemoflagellates reveals similarities in origin, morphology and 

 fiuiction sufiicient to justify classifying them as homologous structures. 



II. Function and Behavior 



In the preceding discussion of tlie different members of the 

 " Binvicleata, " as well as the other flagellates, the function and be- 

 havior of the parabasal body have already been indicated. It is 

 necessary, therefore, only to sum up the evidence on these two points, 

 with a consideration of some of the earlier views on these questions. 



The majoi'ity of protozoologists who liave dealt with this sub.ject 

 have agreed in calling the paraba.sal body a second nucleus, that is, 

 the "kinetonucleus, " and in giving it a rank equal to that of the 

 nucleus, which is then designated the trophonucleus. The one notable 

 exception to this is Doflein. He objects (1911) to the order Binueleata 

 on the ground that the nuclear nature of this structure in trypano- 

 somes has not been proven, and also that trypanosomes are not the 

 only flagellates which possess "kinetonuclei. " These objections have 

 been amply confirmed in all work on these forms up to the present 

 time, including even the investigations carried on by tlie supporters 

 of the binuclear theory. 



The views in regard to the function of the parabasal body are 

 denoted by the different names w'hich have been given to it. The 

 French school of protozoologists, following the lead of Laveran and 

 Mesnil (1902), generall.y regard it as the " centrosome, " a supposition 

 for which but little, if any, adequate evidence can be found. The 

 same views on the subject of its function were put forth by Moore 

 and Breinl (1907), who thought it originated by a division of the 

 intranuclear centrosome. 



The use of the term blepharoplast for this structure among the 

 Germans began with the adoption of it by Schaudinn (1904). As 



