THE H^MOPLAGELLATES. 187 



from the uew daughter-one. The new flagelhim, myonemes^ 

 etc., are laid down independently alongside and parallel 

 with the old organellas, arising, exactly as these did, by the 

 great extension of a kinetonucleav spindle. Lastly, the 

 genei-al cytoplasm divides, and two practically equal 

 daughter-Try panosomes result. 



After activ^e movement and multiplication (the latter taking 

 place without any loss of motility) have continued for some 

 time a resting condition succeeds. The parasites now 

 become gregariniform, and strongly recall the similar phase 

 described by Leger (63 and 68) in certain Herpetomonads.^ 

 The Trj^panosome bores into an epithelial cell of the stomach 

 by means of its flagellum, which becomes reduced to a short, 

 rod-like organ, serving to anchor the parasite firmly. Binary 

 fission may go on during this gregariniform condition, and 

 this often leads to the formation of a dense layer of parasites 

 all attached to the epithelium. Besides this superficial attach- 

 ment they may also penetrate far in between the cells, when 

 they assume a rounded form, and lose all traces of the 

 flagellum. Upon the Trypanosomes again becoming active, 

 or trypaniform, the flagellar apparatus is re-constituted 

 by the kinetonucleus. 



This alternation of resting and active periods, accompanied 

 by division, has a limit, dependent upon internal causes 

 (within the parasites themselves) and external ones (due to 

 the reactions of the host). The course of succeeding events 

 may be very varied. The indifferent forms may pass into 

 the blood of the owl, or they may, in certain circumstances 

 which Schaudinn was unable to ascertain, lose their indifferent 

 character and become sexual, either male or female, having 

 the same subsequent development as the male or female 

 Trypanosomes resulting from ookinetes of corresponding 

 character. Finally, if hunger ensue and the gnat is unable 

 to make another meal, the indifferent Trypanosomes gradu- 

 ally die off. 



' See below, in Section II. 



