MITOSIS AND CELL DIVISION IN EUGLENA. 115 



move apart more or less individually in the anaphase and each 

 chromosome undergoes a longitudinal fission as it resolves again 

 into the granular state. The nuclear membrane constricts in the 

 mid line following the movement of the chromosomes to the poles 

 of the nucleus. The endosome lies in the center of the chromo- 

 some mass throughout the process. It becomes homogeneous 

 early in the prophase ; then elongates at right angles to the long 

 axis of the body and constricts in halves preceeding the complete 

 constriction of the nuclear membrane. It resumes its vegetative 

 appearance in the reorganization period. 



The kinetic elements of the flagellum are derived from the 

 endosome and lie in the nucleus during the vegetative life as the 

 intranuclear body. Prior to division this divides ; then moves to 

 the nuclear membrane and, as the nucleus comes into contact with 

 the base of the reservoir, the halves give rise to the blepharo- 

 plasts. Two new axial filaments grow out, one from each new 

 blepharoplast, and unite with the original axial filaments. The 

 axial filaments then become widely separated, splitting the original 

 flagellum as they move apart. The two flagella for the daughter 

 organisms are thus formed and grow out to their normal length 

 following division. The rhizoplast connecting the nucleus to the 

 blepharoplasts persists late into the vegetative stage and possibly 

 throughout the whole of this period. 



LITERATURE CITED. 



Baker, W. B. 



'26 Studies in the Life Cycle of Euglena. i. Euglena agilis. BIOL. 



BULL., 51 : 321-362. 

 Belaf, K. 



'16 Protozoenstudien I. Amoeba diplogena, Astasia levis, Rhynocho- 



monas nasuta Klebs. Arch. Prot, 36: 14-51- 

 Berliner, E. 

 '09 Flagellatenstudien. Arch. Prot., 15: 297-326. 



Haase, G. 



'10 Studien iiber Euglena sanguinea. Arch. Prot., 20: 47-59- 



Hall, H. P. 



'23 Morphology and Binary Fission of Mcnoidium incuri'inn (Fres.) 



Klebs. Univ. Calif. Publ. Zool., 20: 447~4?6. 

 Hartmann, M. and Chagas, C. 



'10 Flagellatenstudien. Mem. Inst. Osw. Cruz., 2: 64-125. 



