ill the lungs, the eggs do not pass in the feces, but hatch in the body 
of the host animal. In such cases larvae are found in the feces. An 
illustration of this is the cat lungworm, Synthetocaulus abstrusus. The 
eggs of this worm develop in the alveoli of the lungs and the young 
worms hatch, make their way up the trachea and are swallowed, ap¬ 
pearing in the feces as larvae (Fig. 15). 
Numerous objects, such as plant spores, simulate parasite eggs in 
feces to some extent. Among other things which may be present 
and which must be eliminated from consideration as worm eggs, are 
the eggs of mites, both parasitic and free-living. An illustration of 
the eggs of a sarcoptic mite- (Fig. 16) is given here. These eggs are 
elliptical and rather large, being in the case of Saroptes scabiei canis 
of the dog about 150 microns long by 80 microns wide. In an early 
stage the contents of the egg are granular; later the development of 
the mite in the egg makes an identification easy. 
25 
