testine; 0,067 mm. wide. Nerve collar situated 
approximately at the junction of the anterior 
and the posterior parts of the oesophagus. 
Excretory pore opening in the ventral sur- 
face, at the height of the middle part of the 
oesophagus. Mouth very small, hexagonal, 
surrounded by six smal! papillae arranged in 
two lateral series each with three papillae, 
ihe middle ones being the most voluminous 
Buccal cavity small, cylindro-conical with 
strong chitinous support, more dilated in the 
posterior part where are small sub-quadran- 
gular teeth. Oesophagus rectilinear, with pi- 
riform dilatationin terminal part; united with 
spheroid bulb by a short canal. Intestine with 
dilated initial part, quite straight. 
Male: Nerve collar 0,296 mm. from ce- 
phalic end. Anal orifice at 0,65 mm. Oeso- 
phagus: 0,925 mm. in length. Bulb abont 
0,254 mm. in diameter. Sucker cleft-like, ellip- 
soid without chitinous armature, surrounded 
by radiating muscular fibres, arranged in two 
groups one on each side ofthe organ; lower 
limit 0,71 mm. from caudal extremity; length 
0,211 mm. Almost no caudal expansions. Ge- 
nital papillae eieven pairs in number volu- 
minous, thus arranged: three pre-anal ven- 
tral ones; the first very voluminous at the side 
of the upper third of sucker; the second 
large, half way between sucker and anus; 
the third slightly smaller above the ano-geni- 
tal orifice ; two ad-anal large and equal, one 
lateral, another ventral, six post-anal: four 
ventral; two larger ones near the anus, two 
much smaller ones near the caudal apendix, 
two lateral: one voluminous, one just above 
the second ventral group very small; its 
positiony varies from above the large 
lateral ones to below the penultimate ventral, 
one. Two spicules of slightly differing length, 
sinuous, Slightly dilated in the proximal, shar- 
ply pointed in the distal extremity: 1,694 
mm. in length; width 0,059 mm. Gubernacu- 
lum almost straight measuring 0,194 Anus 
1,164 from caudal extremity. 
Female: Nerve collar 0.338 mm. from 
head. Excretory pore 0,508 from same. Oeso- 
phagus: 1,156 mm. long. Diameter of bulb 
0,282. Vulva slightly protruding, just above 
24 
the middle of the body; vulvar orifice qua- 
drangular. Ovijector going from vulva towards 
cephalic extremity measuring 0,899 mm. Ves- 
tibule generally containing three or four eggs, 
with thick muscular walls and slight chiti- 
nous lay3r 0,448 mm. long. Sphincter 0,169 
mm. long. Horn with thin muscular layer, 
ample lumen, containing five or six eggs 
0,398 long. Uterus with divergent branches ; 
uterine hooklets surrounding the gut in 
its whole lenght. Ellipsoid eggs with thin shell 
containing embryos when laid, with the fol- 
lowing diameters: 0,067 mm. and 0,050 mm. 
Anus 0,693 mm. from tail end. 
Development: On examining faeces of 
Callithrix jacchus we found several specimens 
of Subulura jacchiand found not only nume- 
rous eggs containing perfectly developed em- 
bryos (vid. Plate XIV fig. 2) but also very li- 
vely larvae with the following caracteristics 
Body with very sharply pointed extremity: 
0,512 mm. long. and 0,12 wide. Mouth round, 
circular, with small vestibulum, 0,012 mm. Di- 
gestive tube rectilinear, with ampulliform bulb, 
0,177 mm. distant from cephatic end, 0,022 
long and 0,006 wide. Anus 0,048 mm. from 
tail end (vid. Plate XIV, fig. 1). In order to 
follow the development of these larvae, we 
made culture media of them, mixing the faeces, 
diluted with water and animal charcoal fine- 
ly pulverised and distributing the material 
in on slides. Some of the slides were expo- 
sed to the light, others we kept in darkness. 
We saw no change either in the eggs or in 
the morphology of the larvae during thirty- 
seven days observations. We only remarked 
that the activity of the larvae diminished pro- 
gressively until it became null within eight- 
een days. 
Habitat; Intestine of: 
Callithrix jacchus L. 
Callithrix chrysoleucus Natt. 
Callithrix melanurus Geoff. 
Midas (M) bicolor Spix. 
Callicebus calligata Natt. 
From Minas Geraes (Lassance) and Rio 
de Janeiro. 
