E. Hindlb 
131 
In consequence Ronbaud (1909), Chatton (1909) and later Dnnkerly 
(1911) prefer to retain the genus Herpetonionas for the biflagellate 
H. miiscae-domesticae and employ the older generic name Leptomonas 
for the uniflagellate forms. 
On the other hand a number of authors (e.g. Patton, 1909; 
Mackinnon, 1910) have denied the existence of a true biflagellate stage 
in H. miiscae-domesticae, explaining the appearance described by Pro- 
wazek as merely a stage in the division of the parasite. Personally, 
I am of the opinion that the structure and mode of division of closely 
related parasites constitute strong arguments against Provvazek’s view, 
but nevertheless it is perhaps advisable to retain the genus Herpeto- 
monas for H. muscae-domesticae, as described by that author. 
Recently Chatton and M. Ldger (1911) have demonstrated the 
presence of an axostyle in Leptomonas drosophilae, and subsequently 
Chatton (1911) showed that the diplosome of H. muscae-domesticae 
was merely the remains of the axostyle, or axoplast. Consequently 
Chatton (1911) is of the opinion that the distinction between Lepto¬ 
monas {sensu Chatton and Alilaire, 1908) and Herpetomonas is purely 
arbitrary, but he prefers to retain the two genera. Alexiefif (1911 ; 
1912) on the other hand assumes the identity of the two but retains 
the name Herpetomonas for the genus; moreover, he criticises Chatton 
and Alilaire (1908) for reviving the genus Leptomonas without having 
examined the type species. 
But whichever name may be shown to be correct, it is certainly not 
legitimate to employ the term Leptomonas for all uniflagellate parasites 
possessing two nuclei, the kineto-nucleus being usually anterior to the 
tropho-nucleus. Also having shown that some species of the genus 
Leptomonas, as emended by Roubaud, may pass through a crithidial 
stage in their life cycle (Dnnkerly, 1911) it is still less legitimate to 
assume that all crithidial forms occurring as true parasites of the 
intestines of insects should be regarded as merely representing stages 
in the life cycle of that genus. 
On account of the fact that many trypanosomes have been shown to 
pass through a crithidial stage Woodcock (1909) has adopted the view 
that all Crithidia found in blood-sucking insects are stages in the life 
cycle of some trypanosome. 
This view has been criticised by both Porter (1911) and Swingle 
(1911) and therefore it is unnecessary to add any further remarks on the 
subject. The latter author has clearly proved that Crithidia melophagi 
is a true insect parasite and not a stage in the life cycle of the sheep 
9—2 
