360 



A Ki;\\ NOTKS OS THK rUOTOZOA PAItASmC IN llllfo irijulilrin 



II<cmogrega- 



rirta 



tuniuensis 



Drepa n idiu m 

 magnum 



Flagellates 



Fioiu this iirraiif^uiiiunt ii stimulus started in one iiiyunciiiu may Iju traiisfcMied to 

 tho next, and thus undulatoiy movement of the membi-ane may be kept up. 



Hjemogregabin.k 



Two forms occur very commonly in this toad. One form or both were present in 

 17 out of 21 cases. Tho period of examination was tho same as above. They wore both 

 far more common in the blood in the earlier part of my stay in Khartoum than in the 

 latter, and as I never found any signs of schizogony in any of the organs, I think it is a 

 fair assumption that this process only takes place in the summer months in cold-blooded 

 vertebrates. I believe that the schizogony stages of similar parasites in lizards found 

 by I)r. Wcnyon were in specimens collected in the warmer part of the year. These stages 

 in warm-blooded animals, the jerboa for instance, seem to take place all the year round. 



The first, and if anything the commoner form of these two hiemogregarines, is found 

 in the blood corpuscle in a firm cyst wall, and is sharply bent upon itself about the 

 middle. The cyst wall is double at the end at which the parasite is bent, and the space 

 between the two layers contains a substance which stains a bright red with Eomanowsky 

 stains and retains the iron haeniatoxylin stain well (Plate XXI., figs. 9-11 and 13). The 

 cyst is not as long as the blood corpuscle. Observed in citrated blood, or in a similar 

 emulsion of spleen pulp the parasite, especially in the latter situation, is often seen free 

 (Plate XXI., figs. 12 and 14). Its movements are fairly rapid, and of a definite gregarine 

 type, contractile waves passing down the body being seldom seen until motion has 

 practically ceased. When the motion begins to slow down, the mucoid thread secreted 

 by the organisms becomes visible, and, after forward motion ceases, this thread has been 

 seen to become corkscrew-shaped. Movement has also been seen in the cyst, the 

 parasite completely turning round inside it. Average size of the cyst is 14ju x 8'8/». 



This parasite is probably the same as that observed in a frog in Tunis, and has been 

 named Hjemugregarina tunisiensis. 



The second and larger hamogregarine is probably Drepanidium magnum (Plate XXI., 

 tigs. 15-19). It lies apparently free in the blood corpuscle, of which it fills the entire length, 

 its two ends being slightly bent over. Size in corpuscle 23^ x 7/i. In films in which the 

 blood corpuscle has disappeared a stained capsule is visible, and, in citrated blood, the ends 

 of the organism are generally still bent as if enclosed. I have never seen this form actually 

 motile, but possibly the large free organism shown (Plate XXI., fig. 18) is of this type. 

 Both forms show a marked rostrum. 



On staining tissue fixed with saturated corrosive sublimate and glacial acetic acid, the 

 nucleus of both these hasmogregarines is found to be that of the definite gregarine type 

 mentioned by Professor Minchin, e.g. a vesicular nucleus containing granules of chromatin 

 on the fibres of a fine network. In these cases there are smaller granules round the 

 periphery with generally four larger granules in the centre. 



I have shown in the drawing some haemogregarines from the river turtle [Triojiyx) of the 

 Nile (Plate XXI., figs. 20-25). The specimen was a young one. I also show a possible 

 schizogony stage of this from a film from the lung (Plate XXI., fig. 25), but as it was the 

 only one I found, I do not place much reliance on it, and, in addition, the films were 

 hurriedly made. 



Protozoa in Intestine 

 Flagellates 



Tricliiiiiuinas and Hexamitus {Octoviitus) are seen very commonly in most cases (Fig. 107). 

 They show no difference from those described by Dobell in the frog in this country or from 

 those described in the mouse and rat by Wenyon, where I have also observed them. 



