[ 2 9 ] 
The (esophagus is not so retractile, is much shorter, only about 
.6 mm. in length. 
2. The intestine is scarcely ever brown in colour and does not 
contain blood. 
3. The alimentary canal is straight, there being no distended coils 
of the testis to displace it. 
4. The rectum ends in the common cloaca in conjunction with 
the vas deferens. The last deserves special mention. 
The anus, merged into the cloaca, is subterminal and distant about 
.15 mm. from the extremity of the tail. Its details cannot be distinctly made 
out, being largely hidden away by the thick spicule and its sheath. 
The muscular system is less developed in the male and the peculiar 
arrangement of the fibres is not so marked. 
Nothing definite can be made of the excretory or nervous apparatus. 
Genital System. 
The genital system is less complicated than in the female. There is 
only one testis—a long narrow organ running parallel to the intestine, 
ikbove it reaches to about the middle of the body ; downwards it terminates 
in a vas deferens which differs in no wise from the testis beyond the fact 
that it is hollow and slightly narrower. Within the testis, large numbers of 
retractile cells may be seen in the living worm. These are the spermatozoa. 
They will be described more fully later on. 
The vas deferens is continued as a stiff spicule which is very retractile. 
This—the anterior spicule—measures .22 mm. in length, and in the living 
stage may be seen to project in and out by means of the strong muscles 
attached to it. 
Lying usually behind it, but occasionally by its side, is a shorter struc¬ 
ture of a similar shape. This is the posterior spicule (sheath of the penis), 
and its length reaches .12 mm. This latter spicule is apparently not con¬ 
nected with the vas deferens. It is also moveable but not so active as the 
anterior spicule (penis proper) and can move independently. 
The anterior spicule is a trumpet shaped organ. Where it is continu¬ 
ous with the vas deferens it is irregularly funnel shaped, the diameter being 
just under .03 mm. (30 u.). As it proceeds outwards, it tapers gradually 
until it finally ends in a slightly bulbous projection and then a sharply 
defined filament. The cuticle round the point of emergence of the two 
spicules is raised forming a prominent ring. 
Two smaller papillae may be seen lying in front of the opening. 
One is situated just anterior to the ring, and the other—a more easily 
detected one—30 u. or .30 mm. still anterior to this. There are, besides the 
above, one or more post-anal papillae, but these cannot always be detected. 
The hinder portion of the male worm is curved on its ventral surface, 
along which a distinct grove may be seen running longitudinally in the 
centre, to admit of the passage of the two spicules. 
It will be seen that the arrangement of the genital organs in the male 
and female worms is best adapted amidst their surroundings for their several 
functions. The openings of both are situated inside the aortic tumour, that 
of the female being in the constricted portion close to the mouth, and that 
of the male being at the posterior extremity but well within the reach of the 
f 
