164 



SOME PARASITIC PROTOZOA FOUND IN 

 SOUTH AFRICA: IV. 



By H. B. Fantham, M.A.Cantab., D.Sc.Lond., 



Professor of Zoology, University of the Witwatersrand, 

 Johannesburg. 



Read July 15, 1921. 



Abstract. 



The present paper records and summarises my work on para- 

 sitic Protozoa since the last meeting of the Association. My 

 previous results have been communicated to this Association at the 

 last three meetings and are published in this Journal, Vol. XV, 

 pp. 337-338, Vol. XVI, pp. 185-191, and Vol. XVII, pp. 131-135. 

 This account provides an extension of our knowledge of the dis- 

 tribution of the parasitic Protozoa in South Africa. 



As before, the term "parasitic" is used in a wide and general 

 sense, and may include saprozoic and commensal organisms, as well 

 as coprozoic forms. 



One of the most interesting organisms has been Cycloposthimn 

 hi pal mat inn, which shows periodic variation in numbers in the 

 infected horses, and appears to be associated with intestinal dis- 

 orders of the character popularly described as "colic." Attention 

 may also be drawn to a new species of Entamoeba in the horse and 

 to the new species of Giardia — in the ox and in the horse — recorded 

 herein. 



The measurements of organisms given in this paper are deter- 

 mined from camera lucida drawings of the organisms made at 

 various known magnifications. 



Sakcodina. 



Entamoeba intestinalis has been observed on rare occasions in 

 the colon of horses as reported by me previously. I have since 

 found it in the caecum of the horses in very small numbers. 



I have also been able to observe what I believe is a new Ent- 

 amoeba in the faeces of two horses showing signs of intestinal 

 malaise. One of the two horses also harboured Cycloposthium. 

 The Entamoeba was present in small numbers. It has much the 

 appearance of Entamoeba histolytica of man, except that it is 

 rather larger and possesses an oval instead of a rounded nucleus. 

 There is a structure usually called a karyosome with a centriole in 

 the nucleus. Like E. histolytica it can and does ingest red blood cor- 

 puscles. The trophozoites were variable in size, but fully extended 

 ones measured 40 w to 50/x by 23/u to 29/n, while rounded ones 

 measured *28/x to 35ju. The rounded, thin-walled cyst sometimes 

 contained chromatoid bars and four nuclei were present in the 



