35i 



Here, as in the case of other trypanosomes, mor- 

 phological appearances often make it a difficult 

 matter to distinguish species. The fact, however, 

 that the trypanosome of one species of fish cannot 

 be transmitted to another species of fish is in 

 favour of the specific nature of the trypanosomes 

 of each species of fish. 



Mode of infection. — This, probably, is effected 

 by ecto-parasites of the fish, especially leeches. 

 Experimentally, it has been shown that leeches 

 can transmit the infection. Inoculation of fish 

 is most successful when made intra-peritoneally. 



1. T.remaki. — Jn the pike (Esox lucius). Never 

 very numerous. Two varieties or species occur : 

 (i) T. remaki, var. parva, 28-30 m long, flagellum- 

 included, by i"4 m broad. The blepharoplast is 

 rather small, (ii) T. remaki, var. magna, 4'5 // long, 

 by 2'5 M broad. , These two varieties resemble one 

 another very closely, except in size. 



2. T. danilewskyi. — In the carp (Cyprinus 

 carpio). 35-45 m long, by 3 m broad. Blepharoblast 

 large. The protoplasm in stained specimens has 

 many chromatic granules. 



3. T. tincae. — In the tench (Tinea tinea). 

 Generally scanty in the blood. Motility very 

 active, and curls on itself. 35 a long, by 2"5-3 m 

 broad. Posterior end is blunt. 



4. T. abramis. — In the bream (Abvamis 

 brama). Recorded by Laveran and Mesnil, but 

 undescribed. 



5. T. gvanulosum. — In the eel [Anguilla vul- 

 garis). They vary in size from 44-80 /^ in length, 

 and 2"5-3 m in width. Very active in their move- 

 ments. , Undulating membrane broad. Posterior 

 end sharply pointed. Stained specimens show 



