1916] Su'czij: Kiiicioiiuclcus of Flaaellntfs 209 



in the trypanosome type of structure, and the other, starting from a 

 biflagellated ancestor, developing along the line of the Polymastigina 

 and the Trichonyniphida. These will be traced out separately, fol- 

 lowed by a final summing up of the evidence therein given, and its 

 application to the binuclear theory. 



1. FIRST LINE— HAEMOFLAGELLATA 



It has been claimed generally that the basal granule or blepharo- 

 plast of the flagellates has originated from the eentriole of the nucleus 

 (Minchin, 1912), which moves out, either remaining in close connec- 

 tion with the nucleus or becoming quite independent of it. The 

 original type of flagellate would, in tliat case, be one in which the 

 flagellum was connected directly with the eentriole in the nucleus, as- 

 suming that the primitive position of the eentriole is intranuclear. 

 This primitive condition without blepharoplast or a basal granule is 

 unknown among the flagellates, and is an entirely hypothetical one. 



One place where the origin or the process of formation of the neuro- 

 motor apparatus in the individual, with its accompanying blepharo- 

 plast, may be actually observed is among some of the amoebae of the 

 Limax group, as in Ndgleria gruberi (Schardinger). This is not the 

 production of minute swarra-spores by the breaking up of tlie parent 

 body, but is, instead, the actual change of an adult amoeboid organism 

 into a flagellated one with blepharoplast and flagella complete (fig. 

 14). The actual transformation may be watched in the living forms 

 and its stages analyzed in fixed material. This change from an adult 

 amoeba to a flagellate has been described by Whitmore (1911) , Alexeiff 

 (1912), and more fully by Wilson (1915) . As shown by the last-named 

 investigator various factors may bring about this change, as a varia- 

 tion in temperature, medium, etc. 



The first outgrowth of the fiagellum appears as a minute bud on 

 the edge of the karyosome within the nucleus. This granule moves 

 out toward the nuclear membrane, drawing after it a slender fibril of 

 presumably achromatic material from the karyosome (figs. 12, 13). 

 When this granule reaches the periphery of the cell or very near it, 

 the flagella make their appearance, and push out beyond the peri- 

 plast. So far as direct observation goes, the material for the blepharo- 

 plast comes from the outer border of the karyosome and the eentriole 

 can still be seen at the center of the karyosome during all stages of 

 the development of the flagella. Its exact origin is thus somewhat 



