NEMATODE HMMATOZOA IN THE DOG. 271 
- together, so as to form a sort of ‘borer,’ by which means, 
possibly, the parasites bore their way through the tissues. 
The alimentary canal is well differentiated, the oesophagus 
occupying above trd of the entire length of the worm: a 
well-marked sphincter-like constriction exists a short dis- 
tance below the mouth, probably indicating the junction of 
the pharynx with the cesophagus. The intestinal canal 
terminates on the convex surface, a short distance from the 
end of the tail; the latter is somewhat blunt, and is tipped 
with a trefoil-like object (glandular ?), communicating with 
a tube and apparently containing a transparent fluid. 
During this period of its growth the worm undergoes a 
moulting process—casting off its skin entirely. When the 
cuticle has become somewhat separated from the body of 
the worm shortly before the ‘ moulting’ actually occurs, the 
continuation of the old cuticle with the lining of the oral 
and anal orifices is very evident, as also the fact that it 
forms a coating to the tri-lobed gland-like object at the 
caudal extremity. 
This process of moulting appears to be repeated several 
times, and each time some slight modification occurs in the 
appearance of the worm, especially at both ends; it also 
increases in size. ‘The prominent papille with which the 
mouth is furnished gradually disappear, and, by the time 
that the worm has acquired a length of about 3ths of an 
inch, reproductive organs can be distinctly made out and 
the sex identified. No ova, however, can be detected in the 
genital tube of the female at this stage, and the spicula in 
the male are not developed until after the spermatic tube 
and the sheath of the retractor muscles of the larger spicule. 
The esophagus is proportionally much shorter, and the tri- 
lobed object at the caudal extremity almost completely 
disappears. 
The worm gradually acquires a more decidedly pinkish 
hue, and instead of occupying a little tumour alone, as it 
did when very small, it appears to make its way into some 
adjoining tumour. Other worms also migrate to this, so 
that one tumour may be common to several parasites. It 
should, however, be noted that they do not occupy a single 
cavity, but each tumour is tunnelled in various directions, 
so there is frequently some difficulty in pulling out the 
parasites without tearing or otherwise injuring them. 
Sometimes they may be seen to have crept outside the 
tumour, lying between it and a serous covering investing 
the artery, or a parasite may be seen emerging through a 
minute orifice communicating between the tumour and the 
VOL, XV.—NEW SER. T 
