PARASITOLOGY, 127 
the plates. These glands empty into the esophagus 
and the secretion in all probability is a digestive one. 
The neck glands appear as two large spindle-shaped 
cells located within the perivisceral cavity of the 
anterior half of the body, and united with the so- 
called bridge of the excretory system by two longer 
or shorter peduncles of varying calibre. These glands 
are provided with excretory ducts which empty on 
the margin of the buccal lips. It is believed that this 
secretion has something to do with the prevention of 
the ready coagulation of the blood ingested by the 
worm. It has been found by experimentation that 
these glands secrete a poisonous substance which may 
interfere with the general health of the infected 
horse, ass or mule causing an unthrifty condition as 
well as evidence of injury by a production of an 
eosinophilia. 
As a rule we may say of the larger species of 
strongylus, that the Sclerostomum vulgare are found 
principally in the cecum and at times the colon. The 
Sclerostomum edentatum and S. equinum are found 
Principally in the first portion of the colon. The 
Triodontophorus minor is found principally in the 
thickened end of the terminal portion of the large 
colon. The triodontophorus serratus and the Cy- 
lichnostomes are found scattered throughout the 
cecum and great colon. 
The loss of blood caused by myriads of the blood 
sucking kind amounts to considerable and yet while 
nearly every horse harbors a greater or less number 
of the various species here described but few ever 
show any inconvenience. Just to what extent the 
