246 Proceedinfis of the B,oynl Physical Society. 



6. Haemogregarine from blood of Raia micwcellata. 



A Halteridium-like parasite was also found in the red 

 blood-corpuscles of Baia microcellata. This parasite appears 

 to correspond with Hcemogregarina delagei, described by MM. 

 Laveran and Mesnil as parasitic in the erythrocytes of Paia 

 punctata and P. mosaica {C. P. Ac. Sci. Paris, T. 135, 1902). 



The parasite was, on the whole, rare and difficult to see. 

 It is found lying at the ends or sides of the erythrocytes. The 

 creature is about 10 ^ to 16 /a in length, and is usually 

 shaped like a rather thin sausage, though fusiform individuals 

 are also met with. There is no obvious blepharoplast. 

 Vacuoles are occasionally present, as also granules, which 

 stain almost black with methylene blue : in Giemsa prepara- 

 tions the latter do not show up anything like so clearly. 



The nucleus, which is large in size, is either somewhat 

 reticulate in character or shows an irregular arrangement of 

 chromatin round what appears to be a karyosome. At times 

 the boundary of the nucleus is sharp and membrane-like, 

 at others the collection of chromatin granules shows an 

 irregular external boundary. 



Division or schizogonous stages have not been met with. 



I do not at present see any connection between this form 

 and the trypanosome cycle. It is, however, interesting and 

 possibly significant to note that in all the three cases 

 observed the Trypanosome was accompanied by the Halter- 

 idium. This recalls the similar juxtaposition of parasites 

 found in the plaice and flounder. 



In conclusion, I may call attention to two points in the 

 above description on which I desire to lay stress : firstly, the 

 occurrence of a typical blepharoplast within the endocorpus- 

 cular parasite of the python — indicating that it has a free 

 trypanosome stage ; and secondly, the occurrence of a spiral 

 arrangement of chromatin in T. brucei — recalling the condi- 

 tion found in T. halbianii, and confirming the near relation- 

 ship of T. halbianii to the typical trypanosomes, and so 

 indirectly supporting the view that the genera Trypanosoma 

 and Spirochceta are closely allied forms. 



