
Anterior extremity broad and rounded; 
more or less indented near the cytostome. 
Posterior end drawn outin a tail which 
may be half as long asthe body; it is rarely 
wanting, in which case the posterior end is 
rounded. 
Plasm generally finely alve oated. Ecto- 
plasm forming a rigid periplasm, which makes 
all movement impossible. Outer margin dis- 
tinct. A cytostome with chromophilous lip is 
found at the anterior extremity. Length 3—5 
p Width 1-2. It is often curved. 
Nucleus spheric, anterior, sometimes la- 
teral, generally sub-marginal, 1—5 u in dia- 
meter. Nuclear membrane thick; caryosome 
small when present, in which case there are 
generally three achromatic filaments, in the 
clear zone they attach the caryosome to- the 
nuclear membrane; often there are three or 
four irreguiar and long chromatic granula- 
tions adheiig to the inner side. 
“Three anterior, equal flagella, start from 
the blepharoplast, which is in front of the 
nucleus; they are shorter than the body. 
Another flagellum which runs backwards, 
adhering to the undulating membrane also 
starts from it. In fresh specimens the undu- 
lating membrane can be seen crossing the 
cytostome, 
Habitat: Coecum of Oryctolagus cuni- 
culus. 
Note: 1 have found no references to the 
flagellates inhabiting the coecum of the rabbit, 
Ch. cuniculi is not rare nor is itthe only one 
found. 
Chilomastix rosenbuschii FONSECA, 
1916. 
Redescription: Body elongate, pear-sha- 
ped, almost unvarying in form. Length: 
6—12 u. Width 4—7. 
Anterior extremity rounded, much larger 
than the posterior one and the rest of the 
body; posterior extremity forming a pointed, 
but rather short tail. At the fore end a 
long cytostome which may attain the middle 
of the body; its margin is formed by a 
chromophilous streak which begins at the 
55 

| blepharoplast, in front of the nucleus. In 

fresh specimens an undulating membrane 
is visible inside the cytostome, but it does 
not show after staining. The blepharoplast 
emits three anterior slender and equal fla- 
gella which are somewhat shorter than the 
body; in fresh specimens they seem to emer- 
ge from the cytostomatic opening. 
Plasma differentiated in coarsely alveo- 
lar endoplasm and narrow periplastic layer 
of ectoplasm; the latter stains more intensely 
than the rest ofthe plasm and is so rigid as 
to prevent metamorphic movements. 
Nucleus near the end, rounded, someti- 
mes with a caryosome from 2 to 4 u in dia- 
meter. The chromatin generally takes ithe 
Shape of elongate masses which adhere to 
the inside of the nuclear membrane, they 
are generally narrow and rarely found toge- 
ther with the smallcaryosome, which is some- 
times seen. The nuclear membrane is thick 
and stains deeply; when there is a caryoso- 
me, it may be connected by a more or less 
slender linin filament which stains but lightly. 
At the fore end, near to the nucleus and 
cytostome, I often saw a depression or nar- 
owing of the body as in Chilomastix caprae, 
FONSECA. It is dimple shaped; it begins at 
the anterior end and continues obliquely 
backwards. This depression, combined with 
poverty in nuclear chromatin and smaller di- 
mensions seem to me the features which 
best distinguish Ch. rosenbuschi from Ch. 
intestinalis KUCZYNSKI found in the guinea 
pig, for which it might be mistaken. 
I considering these caracters sufficient to 
to establish a new species for this flagellate 
of the “Viscacha”” which is named afer Dr. 
F. ROSENBUSCH, the argentinian protozo- 
ologist, who kindly helped me to obtain and 
study the material. 
Chilomitus ceviae FONSECA 1915. 
Description: This flagellate shows a very 
marked dimorphism ; but all the intermediary 
stage between the two extremes are found, 
In one form, the body is elongate, from 
12 to 17 y long and about 4 wide, with a 
