644 FAMILY: CRYPTOBIID^ 



defibrinated rabbit's blood was added as in N.N.K. medium. The cul- 

 tural forms resembled the blood flagellates, except that the undulating 

 membrane was less developed. In some the posterior flagellum was 

 detached as a trailing flagellum, giving the organism a likeness to species 

 of Bodo. 



According to Plehn (1903) and Keysselitz (1906), the trypanoplasms are 

 liable to produce various morbid symptoms in the fish, which appear 

 paler than normal fish do, and may show oedematous swellings of the body. 

 In some cases there is marked loss of vitality, terminating in death. 



Transmission, ■ — In nature the trypanosplasms are transmitted from 

 one fish to another by leeches. Leger, L. (1904e), noticed that numerous 

 trypanoplasms occurred in the intestine of leeches {Hemiclepsis marginata) 

 which had fed on infected fish (Fig. 240). He also saw small forms in a 

 species of Piscicola which had fed on infected minnows. Brumpt (19066) 

 found that T. guernei of the bull-head and T. barbi of the barbel multiplied 

 in the intestine of Piscicola, while T. ahramidis of the bream developed in 

 H. marginata. The question of transmission was studied more completely 

 by Keyssilitz (1906) in P. geometra (Fig. 245). According to him, there is 

 at first a conjugation in the crop of the leech of forms which he regarded as 

 gametes. The zygote thus formed has no flagella, but is an ovoid body con- 

 taining a nucleus and kinetoplast, each of which is supposed to be the result 

 of fusion of the corresponding structures of the gametes. No confirmation 

 of this process has yet appeared. In the crop of the leech there is active 

 multiplication of the flagellates by fission till a large number is present. 

 These vary very much in size and shape, but there is a tendency towards 

 the production of small slender forms, which eventually make their way 

 into the proboscis sheath. It is presumably these slender proboscis 

 sheath forms which enter the wound inflicted by the leech in the act of 

 feeding. Multiplication was also noted to take place for a short period in 

 Hirudo medieinalis. 



Robertson (1911) studied the development of the trypanoplasm of gold 

 fish in England in Hetniclepsis marginata and Piscicola sp. (Fig. 264). 

 About four to five hours after a young leech had fed, dividing trypano- 

 plasms could be seen in the crop. These appear to be somewhat broader 

 than the blood forms which were ingested. Multiplication proceeds till, 

 on the second day, slender comma-shaped forms make their appearance. 

 All intermediate types between these and the broad forms are still present. 

 After some days the slender forms move forwards to the proboscis and 



1. Form in blood of goldfish. 2. From crop of leech forty-four hours after feeding. 



3. From crop three and a half days after feeding. 4. From crop six days after feeding. 



5. From crop six days after feeding. 0. From crop seven days after feeding. 



7. From crop ten days after feeding. 8. From crop twenty-five days after feeding. 



