STUDIES IN THE LIFE-HISTORY OF EUGLENA. 347 



figure. In this position the bodies seem to be homologous to the 

 centro-blepharoplasts of Trichomonas and other forms as de- 

 scribed by Kofoid. 



(3) The chromatoid residue left on the nuclear membrane after 

 the blepharoplast-basal body complex is freed, as described above, 

 is homologous to the parabasal body of many parasitic flagellates 

 as well as to the so-called "kinetonucleus" of Trypanosomes. 

 This homology is indicated by the position of the residue with 

 relation to the poles of the division figure and its connections with 

 the endosome and blepharoplast. 



Examination of Text-Fig. B indicates the homologies suggested. 



Mitosis. 



Many cases of "amitosis" were described by the earlier 

 observers of division stages in the Protozoa. More refined 

 methods of technique have enabled later workers to determine, 

 however, that amitosis is of rare occurrence in this group as it is 

 in Metazoa. Nagler (1909) designated what had been previously 

 called "amitosis" in amoeba and many other Protozoa, as 

 "Promitosis," in order to differentiate this type from mitosis as 

 found in Metazoa and Metaphyta. He says: "Fiir die soge- 

 nannte Amitose der Protozoen fiihrt man daher am besten eine 

 neue Bezeichnung ein und definiert sie als eine Kernteilung, die 

 weder ausgesprochene Mitose, noch Amitose ist und sich char- 

 akterisiert durch die Teilung eines Nucleolocentrosoms, des Cary- 

 osoms. Ich schlage deshalb fiir diese Teilungsform den Namen 

 Promitose vor." 



Chatton (1910) distinguished three types of mitosis, charac- 

 terized as follows: 



(1) Promitosis Division center within the karyosome, nuclear 



membrane persistent, chromosomes formed from the 

 peripheral chromatin. 



(2) Mesomitosis Division center outside the karyosome, nuclear 



membrane persistent, chromosomes from the karyosome. 



(3) Metamitosis Division center outside the nucleus, nuclear 



membrane disappears, chromosomes from the nuclear 

 chromatin. 



