134 THe OtTTawa NATURALIST. [ October 
Though Gordius has no jaws and not the slightest traces of 
biting or masticating organs, the round mouth-opening can be 
very distinctly seen in my specimen, when viewed in full face,—a 
small circular pore, lixe a black spot in the centre of the finger- 
like anterior tip. It is not situated towards the ventral side as in 
Grenacher’s Philippine specimens, in which the head-end is very 
obtuse and bluntly flattened terminally. The lumen or chamber 
of the gullet, viewed from the dorsum, appears as a hair-like tube 
in optical section and is surrounded by a pale fibrous matrix, with 
striations passing forwards, the tissue becoming denser immedi- 
ately posterior to this lighter anterior area. Microscopic sections 
show the gullet to be a minute tube with a simple epithelial wall. 
The body becomes gradually thicker posteriorly, and the tail end 
in the male Gordius aquaticus is split, the two halves separating 
like two cotyledons with an internal rounded projection between 
them. In Gordius varius, according to Kingsley’s drawing, given 
by Packard, the terminal cleft is trifid and much more marked 
than in other species. Gordius ornatus, according to Grenacher 
(and shewn in his fig. 1, Taf. xxiii ), exhibits a simple blunt ter- 
mination with a centrally situated cloacal aperture. My specimen 
is apparently a female; yet the posterior end shows a slight indi- 
cation of bifidity, a central depression being discernible: but no 
terminal aperture can be made out. 
There are no traces of eyes or other sense organs ; nor have 
glands, a water-vascular system, or definite nerve structures been 
determined beyond question in our common species. 
species differ greatly in the details of their anatomical features. 
Thus, in Gordius aqguaticus the external cuticle, save for a few 
corrugations near the head end, is smooth. As the creature curls 
about, irregular creases, usually transverse, appear: but in Gor- 
dius ornatus remarkable protruding sense-organs are described by ~ 
Grenacher. These structures have the character of cuticular 
mounds, and when highly magnified, are seen to consist of a 
bundle of stout threads, projecting like tendrils with a circle of 
papilla around them. The tail region in Gordzus aquaticus is 
The various 
