22 
Fig. 4. Photomicrograph of median cross section 
through an adult female eyeworm. 
The cuticular buccal capsule is six-lobed 
and, as is characteristic of the Thelaziidae, is 
divided into two chambers, the anterior pro- 
tostom and the posterior mesostom. The 
esophagus is of the typical spirurid type and 
is approximately 1.5 mm. in length. It is dis- 
tinctly divided into a short anterior muscular 
portion and a posterior glandular portion. 
The lumen is restricted and triradiate when 
viewed in cross section. A well- developed 
esophageal-intestinal valve separates the eso- 
phagus from the intestine. 
The thin-walled intestine extends almost 
the entire length of the body, varying only 
slightly in diameter, and joins the esophagus 
anteriorly and the rectum posteriorly. The in- 
testinal wall is composed of a single layer of 
short, ciliated columnar cells. The rectum is 
thick-walled and muscular and terminates at 
the ventral anus in the case of the female. In 
the male, the ejaculatory duct joins the rectum 
ventrally to form the cloaca. 
PACIFIC SCIENCE, Vol. V, January, 1951 
The excretory system is of the simple H or 
oxyuroid type. From the ventral pore the 
common excretory duct extends dorsally 
through the large excretory cell and divides 
on the ventral side of the esophagus to join 
the two lateral excretory canals. These lie em- 
bedded in the lateral lines of the body wall. 
The lateral lines, which extend almost the en- 
tire length of the body, are, apparently, each 
a single large multi-nucleate cell. The lateral 
canals terminate posteriorly at the latero- 
caudal papillae. 
A nerve ring surrounds the esophagus, 
cephalic of the excretory pore. In association 
with it are four large ganglia, two dorsal and 
two ventral, and a number of smaller cells. A 
dorsal and a ventral nerve cord extend pos- 
teriorly the length of the body, and several 
smaller nerve fibers extend into the cephalic 
region. 
The mature male possesses two spicules of 
unequal length, both of which are cuticular 
in nature, transversely striated, and hollow. 
The shorter, which is "trough-shaped,” mea- 
ures about 200 ^ in length by 30^t in maxi- 
mum width, is only slightly protrusible, and 
acts primarily as a guide for the longer, more 
slender spicule. The long spicule is 3 to 4.2 
mm. in length by 10^ in maximum width and 
is capable of being protruded from the cloaca 
almost its entire length. A short muscular 
ejaculatory duct extends anteriorly from the 
cloaca and terminates in a thin-walled seminal 
vesicle, an uncoiled organ extending over 
half the length of the body. The single long, 
coiled testis fills the remainder of the body 
cavity. 
In the female the vulva, which measures 
46 to 51 m in diameter, is located ventrally in 
30 ^ 
Fig. 5. The short, "trough-shaped” spicule of the 
adult male eyeworm. 
