THE LEUCOCYTOZOA 263 



the infected animals has been reported. Some of the white 

 mice harbouring L. musculi soon died, but I would not be 

 certain that the Leucocytozoon was the sole cause of death. 



IX. Nomenclature 



Some difficulty has arisen latterly regarding the exact name 

 of the genus to which the Leucocytozoa, especially those of 

 mammals, are to be referred. Laveran and Mesnil place the 

 mammalian forms in the genus Hcemogregarina. With all due 

 respect to the wide knowledge and authority of the French 

 protozoologists, I cannot agree with them ; but follow James 

 and Patton in referring the mammalian parasites to the genus 

 Leucocytozoon. James and Patton have the advantage of first- 

 hand knowledge of the group. 



The genus Leucocytozoon was suggested by Danilewsky for 

 the parasites of the leucocytes of owls ; and Liihe has given 

 the name L. ziemanni to the parasite first described by 

 Danilewsky, which Ziemann had called L. danilewskyi in 

 a different species of owl. The exact nature of the host-cell 

 of Danilewsky's parasites of birds is still doubtful. Laveran 

 believes that the host-cells are really young red blood 

 corpuscles, and refers avian Leucocytozoa to the genus Hcvm- 

 amceba, though it must be admitted that the avian Leucocytozoa 

 are not markedly amoeboid in shape, and melanin pigment is 

 not present in them, as it is in most Hcemamceba?, for Laveran 

 includes the strict malarial parasites in the genus Haemamceba. 



Regarding the genus Hcemogregarina, Laveran uses it in a 

 wide sense to include the genera Hcemogregarina (sensu strictu), 

 Karyolysus, and Lankestcrella of other authors. Laveran's genus 

 Hcemogregarina is really more of the nature of a subsection of 

 the Haimosporidia, and is wider than a real genus. Further, 

 the genus Hcemogregarina otherwise only includes parasites 

 inhabiting the red corpuscles of the blood. The red corpuscles 

 parasitised may be those of reptiles, amphibia, or fishes, as well 

 as the remarkable parasites from the jerboa found by Balfour, 

 from the gerbil or Indian field rat by Christophers, and from 

 certain marsupials by Australian workers. Surely the genus 

 Hcemogregarina is very large in whatever sense it is used. The 

 Haemogregarines of red corpuscles only occur in leucocytes 

 rarely, when about to undergo the process of phagocytosis. 



It seems to me that the difference in habitat of the Leucocy- 



