60 PARASITOLOGY. 
where infested sheep have recently been kept; by 
being shipped in cars not disinfected after using for 
transportation of infested sheep; through shipping 
centers, unless such centers are controlled by proper 
quarantine regulations; by the introduction of an 
infested sheep into a bunch not infested; or, by being 
driven over a trail recently followed by scabby 
sheep. 
_ Psoropres CoMMUNIS, variety Capre (Capra—a goat). 
Produces scabies in goats in the same manner as 
the Psoropt in sheep. 
SYMBIOTES COMMUNIS, variety Equi (Equus—horse). 
Synonym.—Foot-scab parasite. 
fistory.—Symbiotic scabies is not common. It 
has been found in some parts of the old world, and 
is more prevalent among coarse horses and those 
that are poorly cared for. 
Description.—This mite is a trifle smaller than the 
species of the two previous genera. The rostrum is 
nearly as wide as long. 
Animal Intested.—The horse. 
Condition Produced.—It produces scabies of the 
legs, usually in the region of the fetlock and pastern 
of the posterior extremity. In later stages the 
scabby condition extends up the leg, possibly as high 
as the body. The skin becomes thickened and rigid 
and the legs swollen. Cracks may be formed in the 
pastern region from which may be found a secre- 
tion of a fetid nature. The parasites live in colonies 
under the scab. 
Treatment.—Thoroughly scrub the affected parts 
