A number of the figures are taken from Railliet’s Traite de 
zoologie medicale, a work which has been for almost thirty years 
the most satisfactory reference book of veterinary parasitology. It 
is a matter for regret that this splendid work has never been issued 
in revised editions and brought up to date. At the present time it 
is almost impossible to purchase copies of the sole edition printed. 
In examining the feces of dogs, cats and foxes for parasite eggs, 
there are certain eggs which are very commonly present, and for this 
reason these eggs are figured here. However, it is the uncommon 
Fig. 2. Taenia hydatigena. A, egg as seen mounted in glycerine. B, egg after treat¬ 
ment with a concentrated potash solution, x 350. From Railliet, 
1893, after Laboulbene. 
thing which is most perplexing, and for this reason the eggs of some 
of the rarer parasites are also figured. Among the commoner species 
present are tapeworms of the genera Taenia and Dipylidium and 
nematodes of the genera Belascaris, Toxascaris, Ancylostoma and 
Trichuris. 
In the genus Taenia, the egg forms with a thin shell, with or 
without filaments, and the embryo, or onchosphere, lies inside of this 
Fig. 3. Echinococcus granulosus. Eggs, x 245. From Blanchard, 1889, after Krabbe. 
enclosed in a thick, radially striate shell called the embryophore. As 
found in the feces only the embryophore and the contained embryo, 
or onchosphere, are present as a rule. This embryophore is com- 
monly termed the egg and is so termed in this paper. The con¬ 
tained embryo is armed with six small hooks which may be seen 
without difficulty under the ordinary powers of the microscope. The 
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