When the female is in the body cavity, the eggs are passed into the 
abdominal cavity and are largely picked up by the omentum in its role 
of protector against foreign objects. 
Acanthocephalids, or thorny-headed worms, are rare in dogs and 
cats, but they sometimes occur, and one species, Oncicola canis, has 
been found in the United States. The eggs have three shells. The 
eggs of Echinopardalis pardalis (Fig. 13) of the cat are 53 to 63 microns 
Fig. 15. Synthetocaalus abstrusus. Larva, x 150. From Railliet, 1893. 
long by 38 to 42 microns wide. The egg sizes for O. canis do not 
appear to have been reported. 
The tongue worm, Linguatula serrata, occurs in the nasal cavities 
of the dog, fox and other animals. The egg (Fig. 14) is elliptical, 
90 microns long by 70 microns wide, and contains an embryo when 
deposited; the embryo has two pairs of bifurcated appendages. The 
eggs of the tongue worm, which is regarded as a degenerate arachnid. 
A. B C. 
Fig. 16. Sarcopies scabiei. Eggs in various stages of development, x 150. 
From Railliet, 1893. 
are expelled in sneezing, but probably some of them are swallowed 
and pass in the feces. This parasite has been reported only once from 
the dog in the United States. 
In the case of certain nematodes, such as some of those occurring 
24 
