PROTOMONADIDA 



153 



Trimastix marina Kent (Fig. 57, a). About 18 microns long. 

 Marine. 



Genus Dallingeria Kent. Small; with drawn-out anterior 

 end. 



Dallingeria drysdali Kent (Fig. 57, b). Small fresh water 

 form. Body length is less than 6 microns. 



Fig. 57 a. Trimastix marina. X625 (After Kent). 



b. Dallingeria drysdali. XIOOO (After Kent). 



c-h. Costia necatrix. c, d, (X 600 after Weltner); 

 e, f, (X1050 after Moroff); g, cyst (X1050 

 after Moroff); h, two individuals attached 

 to the host fish integument (X375). 



Family 10 Costiidae 



With four flagella; two equally long and the other two 

 equally short. 



Genus Costia Leclerq. Body oval in front view; pyriform 

 in profile. Along one side, there is a funnel-like depression, 

 from the bottom of which the flagella arise. Ectoparasitic on 

 fish. 



Costia necatrix (Henneguy) (Fig. 57, c-h). Body 10 to 20 

 microns long by 5 to 10 microns broad. A single compact 

 nucleus central; a contractile vacuole. Asexual reproduction 

 is by longitudinal fission. Spherical uninucleate cysts measure 

 7 to 10 microns. When present in large numbers, the skin of fish 

 appears to be covered with a whitish coat, and it is thought 

 that the organisms are responsible for the death of young fish. 



References 



Christophers, S. R., H. E. Shortt and P. J. Barraud. 1926 

 The morphology and life-cycle of the parasite of Indian 

 kala azar in culture. Indian Med. Res. Mem. 



