ON THE DEVELOPMENT OF BILHARZIA HAJMATOBIA. G37 
the Vienna Academy, the choice of several systematics and 
others fell upon my title, which had the additional advantage 
of handing down the true discoverer’s name to posterity. In 
a letter which I received from Dr. Weinland (dated Sep¬ 
tember 6th, 186l), that able helminthologist willingly aban¬ 
doned the claims of Schistosoma , remarking that u the generic 
term Bilharzia has the preference/’ On the other hand, Pro¬ 
fessor Leuckart, disregarding the remarkable structural diver¬ 
gences which he has himself so fully described, is content with 
the old generic name of Bistoma (or, rather, Bistomum)', 
but, if this view were adopted and retained, it would alto¬ 
gether upset our notions of group-equivalency, and virtually 
relegate to a genus the wider functions of a family or sub¬ 
order. 
The professional interest attaching to this entozoon is so 
considerable, that I am constrained to correct some other 
errors and misrepresentations which have crept into the 
literature of the subject. it is well known—and I have 
myself been at some pains to recognise the fact, both in my 
larger treatises on Entozoa and in the article c Helminthes, 5 
contributed to Dr. Gunther’s Zoological Record for the year 
1865—that Dr. John Harley was the first physician who 
recognised the existence of the Bilharzia disease as occurring 
in Southern Africa. In other words, he proved to demon¬ 
stration that this parasite w r as the true cause of the endemic 
hsematuria of the Cape of Good Hope. This discovery con¬ 
stituted a positive advance in our knowledge of the causa¬ 
tion of urinary disease; and it likewise contributed materially 
to enlarge our ideas respecting the geographical distribution 
of a truly remarkable entozoon. 
In the original memoir by Dr. John Harley, it was not 
unnatural, perhaps, to find that the author regarded the 
parasite to which the Cape ova and embryos were referable 
as a distinct species, especially as he was then, as now, by his 
own confession, totally unacquainted with the adult ento¬ 
zoon. A similar misinterpretation occurred to myself in 
respect of the Bilharzia which I found in the monkey; but I 
soon afterwards abandoned the position, when Leuckart dis¬ 
puted the grounds on which the determinations were based, 
and sent me some adult Egyptian specimens to compare 
with my so-called Bilharzia magna. Dr. John Harley, how¬ 
ever, seems very reluctant to acknowledge the specific 
identity of the North and South African fluke-hecmatozoa. 
Thus, in his recently published third communication to the 
lioyal Medical and Chirurgical Society, he says :— (e My 
position with regard to the question is pretty much the same 
