PARASITES OF THE ALIMENTARY TRACT 57 
PARASITES INHABITING THE ALIMENTARY CANAL 
OF THE HORSE. 
Csophagus and Stomach. 
Strongylus Axei.—This is a small filiform worm, 
usually about 6 or 7 millimetres in length. It coils 
itself up under the mucous membrane in the form of a 
small nodule. It causes no symptoms, and is of little 
clinical importance. 
Filariide.—Two Spiroptera may inhabit the stomach 
of the horse. These are Spivoptera megastoma and 
Spiroptera microstoma—i.e., the large-mouthed and 
small-mouthed Spiroptera. Their average length is 
I centimetre (2? inch). They may be 
found free in the cavity of the stomach, 
but more frequently embedded in raised 
nodules in the mucous membrane, chiefly 
in the cardiac portion, and ranging in 
size from a pea to a walnut, with a 
small aperture at the summit. As the 
nodules grow older they become sur- 
rounded by connective tissue, and finally 
by acalcareous capsule. They appear to 
be more common in the ass than in the 
horse. Aa - abet Fic, 11.—Larva 
They may produce chronic indiges- oF Gastro. 
tion, or even gastritis, with ulceration PHILUS EQui. 
: The horse 
and slight hemorrhage. dibest 
Gastrophilus Equi Larve.—The com- 
mon horse “ bot’’ is the larva of the fly known as the 
Gastrophilus, or Estrus equi. The latter is a compara- 
tively large fly, with the proboscis directed forwards. 
The colour is a mixture of orange, yellow, and brown. 
The wings each show a light brown bar and two ter- 
minal spots of the same colour. It is a common 
parasite in the stomach of the horse, especially in those 
