C. C. Dobell 
289 
others have already adopted this system. The nomenclature which calls 
upon the observer’s friends to supply the specific names of the parasites 
may lead to much confusion, and is heartily to be condemned [e.g. the 
haemogregarines of two species of python are called “ H. pococki ” and 
“ H. shattocki” by Sambon], And although the rules of zoological 
nomenclature are purely arbitrary, it is advisable—even for medical 
men—to adhere to them for the present. 
Some confusion has arisen through the names of the snakes examined 
by various observers. For example, Langmann in 1899 described 
haemogregarines under “ the generic name of haemosporidia ” (sic) in 
Spilotes couperi. In 1901, Lutz described “ Drepanidium serpentium” 
in Coluber corais. In C. corais Sambon (1907) also described a similar 
parasite, and without taking any notice of previous workers, named it 
“ Haemogregarina rarefaciens ” Now the snakes are all of the same 
species 1 in reality, and it is not improbable that the haemogregarines 
are also identical. 
Another slight confusion in nomenclature has crept in through 
Borner (1901), who gave a table with a list of five haemogregarines and 
their hosts. Unfortunately, only one parasite is given to its proper 
host, the remaining four being distributed at random. This mistake 
has, apparently, been unwittingly copied by Minchin in his beautiful 
account of the Sporozoa (1903): so that three errors occur in his list of 
parasites and hosts. 
At present nothing is known of the way in which haemogregarines are 
transmitted from snake to snake. Transmission may perhaps occur 
through the agency of an intermediate host (e.g. a tick) 2 or by way of 
the alimentary canal (as already described in similar frog parasites). 
The method of multiplication appears to be by schizogony in the 
blood corpuscles—either whilst in the general circulation or in the 
viscera (spleen, lung, etc.). 
No sexual process of any sort is known, and it is doubtful whether 
the forms described as males and females really are such. It will thus 
be seen that these animals afford a wide field for future work. It will, 
however, be needless for me to give further details regarding the various 
species. Instead, I have endeavoured to give as complete a bibliography 
as possible (p. 294) and have appended to my own observations a list of 
1 My authority for the names of the snakes has been throughout Boulenger’s Catalogue 
of Snakes in the British Museum. 
2 Prowazek (1908) describes developmental stages (cysts etc.) in a pentastomid, 
Porocephalus. I regard these as exceedingly doubtful. 
