THE H^MOFLAGELLATES. 271 



immediate surroundings and conditions. There can be no 

 doubt that such is the case in those forms for which the cor- 

 rect orientation of the body is known (cf. on the one hand 

 Trypanomorpha, and on the other the delicate tactile and 

 sensory beak of Trypanoplasma and the allied Trypano- 

 phis), and there is no reason to suppose that the same is not 

 true for the numerous uniflagellate forms. In other words, 

 we may regard the sensitive or physiological end of the 

 body as homologous throughout the group. 



Among the biological processes in which the sensitive ex- 

 tremity may be expected to take the lead are the following : 



(1) Attachment. — Schaudinn's discovery that Trypano- 

 soma C H £6 m amoeba'^) ziemanni, when about to enter 

 upon a resting phase, attaches itself to and penetrates a 

 leucocyte by its non-flagellate extremity, is of the greatest 

 importance in this connection. This manner of fixation is in 

 sharp contrast to that met with in Trypanomorpha and 

 other Herpetomonadine forms. Although the mode of 

 attachment in Trypanoplasma is not yet known, there can 

 be no doubt that, if it occurs, fixation takes place by the 

 anterior end, as Keysselitz (1. c.) has found is the case in 

 Trypanophis, the short active beak or rostrum of which 

 itself probably serves this purpose. In the case of most Try- 

 panosomes attachment has not, so far, been described. There 

 are, however, one or two observations on record with regard 

 to certain species of Trypanosoma, which tend to show that 

 fixation occurs in these also by the non-flagellate end (see 

 above, p. 173). 



(2) Agglomeration. — Whatever its exact meaning, it is 

 most likely that this peculiar phenomenon is a biological 

 feature of definite import. This seems indicated, for instance, 

 by the fact that — in what may be regarded as normal cir- 

 cumstances, if not, indeed, under all conditions ^ — the union, 

 in any particular case, occurs in a constant manner. More- 

 over, as already described, the mode of agglomeration and 

 that of attachment differ in exactly the same way in 



See Section VII (b), with reference to " rosette-formation " in cultures. 



