206 C. CLIFFORD DOBELL. 
sionally present. Of Bacteria there is an immense number 
of species, for the most part undetermined (cf. 11), belong- 
ing to the genera Bacillus, Micrococcus, Spirillum, 
Sarcina, etc. Several species of yeast (cf. 18) are also 
commonly to be found. And there are several different other 
fungi, the most remarkable of which is Basidiobolus 
ranarum Hidam. The cysts of this organism are common, 
and might be mistaken for those of Chlamydophrys or 
Copromonas, though they are usually a good deal larger. 
Other developmental stages of this very interesting fungus 
are also quite often encountered, as the cysts germinate in 
the feeces. Then the metazoan parasites must be mentioned. 
These are worms of different sorts—trematodes (Distomum, 
etc.), nematodes (Strongylus, Oxysoma, etc.), and an 
occasional cestode (Tenia dispar). The eggs of these 
forms—especially those of nematodes—are also usually to be 
found in abundance. The other organic particles which one 
encounters are chiefly degenerating epithelium cells and 
blood-corpuscles. Then, in addition, there are all the thousand 
and one undigested animal remains of the host’s diet— 
remains of insects, bits of chitin, sete of earthworms, fat 
droplets, ete.—together with shells of diatoms and desmids. 
I have also found the unopened and apparently intact spores 
of Monocystis! (from earthworms—several species) and 
Adelea ovata (from centipedes). Very many inorganic 
particles—e.g. various crystals, sand grains, etc.—are, of 
course, also present in greater or less numbers. 
I will now proceed to the detailed description of the 
organisms whose life histories have especially engaged my 
attention. 
A. FLAGELLATA. 
(1) The Trichomonads. 
It has hitherto been universally supposed that but one 
trichomonad occurs in frogs, namely ‘Trichomonas 
1 First noticed, I believe, by Lieberkithn (1854). 
