310 



THE PROTOZOA 



former host. T. helicis, according to Friedrich, passes from one 

 snail to another mechanically in the spermatophores during coitus. 

 The following account refers mainly to the blood-inhabiting species : 

 The body of a trypanoplasm is relatively broader and shorter, 

 less sinuous and serpentine, than that of a trypanosome, and is 

 at the same time softer and more plastic, being limited by an 

 extremely thin periplast. The contractile, often slightly metabolic, 

 body yields readily to pressure, and exhibits in consequence 

 passive form-changes when moving among blood-corpuscles or 



B 



FIG. 134. A, Trypanoplasma abramidis from the blood of the bream ; B and C, 

 T. keyssditzi from the blood of the tench : B, small ordinary form ; G, large 

 form. After Minchin, magnified 2,000. 



other solid particles. The principal structural feature is the 

 possession of two flagella, which arise close together at the anterior 

 extremity from a pair of blepharoplasts or diplosome, or from a 

 single basal granule (Martin). One flagellum projects freely for- 

 wards ; the other turns more or less abruptly backwards, and passes 

 down the side of the body at the edge of an undulating membrane 

 to the hinder end, beyond which it projects freely backwards to 

 a variable extent in different species. In T. gryllofalpce the un- 



