78 
Ghnathostomci siamense (Levinsen) 
provided with simple chitinous hooks arranged in eight transverse rows 
and having their sharp points directed backwards. These hooks 
measure 0 - 015 mm. in length and 0005 mm. in greatest diameter. 
The narrow neck measures only 0‘3 mm. in diameter, but the body 
gradually increases in bulk until at a distance of 1 mm. from the 
anterior extremity it acquires a transverse measurement of 0'6 mm., 
which it maintains until within a millimetre of the tip of the tail. 
For a distance of 4 5 mm. from the neck-like constriction the surface 
of the body is thickly beset with cuticular laminae that vary consider¬ 
ably in shape from before backwards, those most anteriorly attached 
have the free edge divided into three sharply tipped digitations, the 
succeeding plates eventually are found to be much narrower and to end 
in a single tip. 
The posterior half of the body is entirely devoid of armature and 
the cuticle is quite smooth. 
The alimentary canal. 
The digestive tract extends along the whole length of the body as a 
broad tube which terminates in the cloaca within 0T5 mm. of the 
posterior extremity. The mouth is a simple opening devoid of vestibule 
and is guarded by two large fleshy lips T5 mm. broad and about 0'5 mm. 
high. Each lip shows a pair of sessile papillae and a median protrusion 
projecting between them. The lips give exit to the ducts of the paired 
labial glands that lie alongside the oesophagus in the perivisceral 
cavity. 
The oesophagus is a highly muscular organ resembling that found 
in the Ascaridae. It measures in length 2 - 4 mm. and gradually in¬ 
creases in diameter from 0T3 mm. at the level of the neck to 0'45 mm. 
at its widest part just in front of the junction with the chyle intestine. 
The chyle intestine has a fairly uniform diameter of 0'25 mm. The 
exact site of union with the rectum could not be ascertained. 
Labial glands. 
Four very remarkable organs, that from their appearance and con¬ 
nections seem to be excretory glands, surround the anterior half of the 
oesophagus. They are arranged symmetrically but are in no way attached 
to the oesophagus. Cylindrical in form and with rounded distal ends 
they hang in the perivisceral cavity attached only by their discharging 
