242 Leucocytozoa 
it is of some service. One reason for calling the haemogregariniform 
parasites of leucocytes by the generic name Leucocytozoon was the high 
degree of specialisation involved in their habitat. Mr Wenyon, ignoring 
this specialisation, asks can mere habitat be regarded as a generic 
character—and himself supplies the answer in the affirmative by quoting 
the alternation of hosts in the case of “Leishmanial' “a profound dis¬ 
tinction which undoubtedly justifies its inclusion in a distinct genus” 
(from Herpetomonas ). I do not wish to confuse the issue regarding 
Leucocytozoa by entering into this controversy. Capt. Patton and 
Mr Wenyon among others can settle that question. But the high 
degree of specialisation shown by the haemogregariniform parasites of 
mammalian leucocytes is surely more than a matter of “ mere habitat.” 
Further, with regard to habitat being a specific chai’acter, Mr Wenyon 
has some slightly personal remarks, Avhich are entirely his own, and 
from which I most strongly dissociate myself. He says “ Miss Porter 
follows James and Patton, who are stated to have the advantage over 
Laveran and Mesnil, of first hand knowledge of the group. Apparently 
Miss Porter imagines that Laveran and Mesnil and possibly others have 
not this first hand knowledge, but I can assure her that in this she is 
mistaken.” The inference is that of my critic and not mine ; nor did I 
state that James and Patton had advantage over Laveran and Mesnil, 
but that they had first hand knowledge. 
It would not be advisable to continue an argument advanced in the 
“ Remarks on the genus Leucocytozoon ” regarding the association in 
classification of the Leucocytozoa of birds with such parasites as those of 
malaria. Capt. Patton considers the avian Leucocytozoa to belong to 
the genus LLaemamoeba, and I need only say, that in so doing, he 
follows Laveran in this association,—a scientist previously quoted by 
Mr Wenyon as an authority on the Leucocytozoa. 
With regard to the priority of the name Hepatozoon of Miller, 
it should be stated that the first observed and type species of the 
haemogregariniform parasites of the leucocytes of mammals, was that 
parasitic in the dog, and named Leucocytozoon canis by James, a life 
cycle of which in the dog-tick has been described by Christophers. 
Lj. canis being the type species, then Hepatozoon , “ a monotypic genus ” 
(Miller), and the name of a parasite in the leucocytes of white rats, does 
not hold as a generic name for these leucocytic parasites of mammals, 
and even Mr Wenyon writes that “ Miller suggests for the rat parasite 
the name Hepatozoon perniciosum.” Miller did not suggest that Hepa¬ 
tozoon should be the generic name for all the Leucocytozoa of mammals, 
but even stated that as the complete life cycle of many of the parasites 
