244 



H. M. WOODCOCK. 



soraata; differences in detail liave been commented upon in the section 

 on Morphology. 



Longitudinal fission is peculiar because of the fact that the two resulting 

 daughter individuals do not at once separate, but remain united by the non- 

 llagellate ends and take up a position of alignment one with the other 

 (fig. 32 b), either end of the thread being formed by tlie flagellar extremity 

 of one of the two parasites. These double individuals or " couples " 

 constitute very thin, corkscrew-like, spirochietiform threads.* Moreover, 

 further division takes place while the individuals of a couple remain 

 thus joined. Fig. 32 c and D shows successive stages in the longitudinal 



Fig. 32. — a — d, formation and multiplication of " couples " 

 ("Spirocha3ta"-threads) in T. ziemanni; E, F, resting-phases 

 of same ; G, agglomerated cluster of very minute forms. (After 

 Schaudinn.) 



fission of a couple, and the separation of the two daughter couples from 

 each other.^ These couples move indifferently in either direction, now one 

 member leading, now the other. There is at present no evidence as to the 

 particular biological signification, if any, of this occurrence. 



With the assumption by the parasites of a resting phase, the body 

 becomes pear-shaped in form.^ In fig. 32 e is seen a couple in the gregarini- 

 form phase, its two members being joined by their kinetonuclear ends. The 



' The question of the " Spirochsetse " is discussed below, p. 314, et seq. 



^ The writer is not able to gather from Schaudinn's account whether the 

 two members of a daughter-couple then separate before again dividing, or 

 whether further multiplication goes on in a similar manner. 



^ The striking resemblance between such a stage and "Piroplasma" 

 donovani (see below, p. 258, et seq.) hardly needs pointing out. 



