53 



NOTE ON A 

 H^MOGREGARINA OF RAIA BATIS, 



By T. BENTHAM, M.Sc. 



While dissecting a small specimen of Baia batis in March last, 

 a single smear of blood was taken from the auricle. This was 

 stained overnight with Giemsa's solution, after fixing for a quarter 

 of an hour in absolute alcohol. The erythrocytes were found to 

 be infected with a small species of Haemogregarina. Sometimes 

 the parasite was found free in the plasma. The average length of 

 the organisms was about 7 /x , their breadth 2 ^ at the thickest 

 part of the cell. They were usually found lying in the cytoplasm 

 of the erythrocyte, parallel to the long axis of the corpuscle, and 

 they did not displace the nucleus. The parasite was sickle-shaped, 

 pointed at one end, and rounded at the other. There was a large 

 centrally placed nucleus, and at the rounded end a conspicuous 

 vacuolar space. The rest of the cytoplasm contained numerous 

 grains of volutin, or some such substance, and situated near to 

 the vacuole were as a rule two large conspicuous organellse, pro- 

 bably consisting of this substance. In a good many cases two 

 parasites were found in a single erythrocyte, and these always lay 

 parallel to one another, suggesting binary fission. In this the 

 organism resembles Hcemogregarina bigeminiim from the blood 

 of different species of blennies. The parasites were enclosed in 

 a distinct capsule, which was somewhat thickened at both ends. 

 Often from shrinkage of the parasite the edge of the capsule was 

 distinctly visible. Previously, the only species of Hsemogregarine 

 described was from the blood of Raia mosaica. Double infection 

 and size, however, point to the fact that the parasite is closely 

 allied to H. higemimim. 



