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Chapter XXVII 

 THE TRYPANOSOMIDAE 



Trypanosomata and Trypanoplasmata ' 



The Tvypanosomidae comprise two genera^ 

 (i) Trypanosoma, (2) Trypanoplasma. The genus 

 Trypanosoma is characterized by the possession 

 of a longitudinal undulating membrane, the 

 thickened border of which takes' its origin pos- 

 teriorly from a blepharoplast, and terminates an- 

 teriorly in a free fiagellum. Division takes place 

 longitudinally. The genus Trypanoplasma has 

 two flagella, one anterior the other posterior. Both 

 arise from one blepharoplast ; the anterior forms 

 the thickened border of the undulating membrane ; 

 the posterior fiagellum curves around the posterior 

 end of the parasite, and then is prolonged into a 

 fiagellum about equal in length to the anterior 

 one. 



The Trypanosomidae occur in fish, amphibia, 

 reptiles, birds, and mammals. Most of these are 

 very incompletely known, and it is only some 

 species in mammals that have been at all closely 

 studied. 



Trypanosomata of fish. — These are common in 

 tropical fish, but have not yet been accurately 

 described. Those recorded below occur in fish of 

 temperate climes. Among marine fish they occur 

 chiefiy in the cartilaginous fish. The sole is the 

 only osseous marine fish so far found infected. 



