l86 PARASITIC PROTOZOA FOUND IN SOUTH AFRICA. 



each with an amcEboid body, one large flagellum, one pseudo- 

 podiuni relatively fixed in position from which the flagellum 

 arises, and sometimes several other small pseudopodia; (2) 

 amoeboid forms, which are relatively few, produced by the 

 withdrawal of the flagellum and its subsequent absorption; and 

 (3) cysts, which were not frequent, but could be produced from 

 either of the other forms, by expulsion of all food material and 

 becoming round in shape. The ditiiensions of the amoeboid body 

 of the flagellate form are from 38/x to 6o/x in diameter, on measur- 

 ing four specimens. The free part of the flagellum may be 150/x 

 long. The dimensions of two ampeboid non -flagellate forms 

 varied from 30/1. to 56.6/x in diameter. Cysts were 30/* in 

 diameter. The organism is allied to the genus Masfigamoeba 

 ¥. E. Schulze, but the flagellum does not arise from the nucleus. 

 A new genus and species may be created for the organism, 

 namely, Mastigamoebiila africana, with the characters described. 



Mastigophora. — The following flagellata have been found : 

 Critliidia gerridis is parasitic in the alimentary tract of Gerris 

 fossarum, adults and nymphs from Heidelberg, Transvaal, having 

 been found infected by Dr. Porter and myself. Both flagel- 

 late and non-flagellate forms occurred, and the. organisms were 

 very frail in appearance. Multii)lication is by longitudinal divi- 

 sion. A Crithidia has also been seen by us in the alimentary 

 tract of Pycnosoma niarginale from Onderstepoort and Johannes- 

 burg. The flagellate stage usually possesses a blepharoplast lying 

 parallel to the long axis of the body. This organism heeds 

 further study before details can be given. Crithidia nielophagia 

 was found in the alimentary tract of sheep-ke'ds, Melopliagits 

 ovinus, in the Pretoria district. I have pleasure in thanking Mr 

 H. H. Curson for a preparation of the parasite. 



A new Giardia, for which I provisionally propose the name 

 Giardia denticis, has been found on rare occasions in the blood 

 of the silverfish, Dentex argyrosona, and also in its gut. The 

 flagellate forms are from 5.3/* to i6/x long, and from 5.3/i. to 

 8fx. broad. The silverfish were obtained from Kalk Bay. Giardia 

 intestinalis has been observed by me from the intestines of man^ 

 white rats, rabbits and guinea-pigs in Johannesburg. According 

 to some authors, the forms observed in the rodents, as well as 

 those from man, may each be considered a dififerent species. 



Several Dentex argyrosona from Kalk Bay have been found 

 to be parasitised in their blood by a Herpetomonas. Flagellate 

 and leishmaniform stages occurred. The flagellate body measures 

 about 5ju, to 24ju, long and i.^fi to 2.5/x broad. Typical Icishmani 

 form parasites measure 2.5ju. to 4.5/a by 1.5/^ to 2.5ft, and inter- 

 mediate forms can be seen. Dividing forms have also been 

 observed. The parasites are not numerous. The organism may 

 be provisionally named Herpetomonas denticis. This natural 

 occurrence of a Herpetomonas in fish has an important bearing 

 on the origin of Leishmania in vertebrates, as has been demon- 

 strated in other cases by Fantham and Porter, " Journal of 

 Parasitology," Vol. 2, pp. 149-166 (1916). 



