200 
Psyche 
[Aug. -Oct. 
three pairs of tentorial arms, the anterior arms, ptn , the dorsal 
arms, stn, and the posterior arms pot shown in Fig. 13; and in 
the embryo (according to Riley) the posterior arms unite to form 
the body of the tentorium etn, while the anterior arms unite to 
form the plate itn, and they also give off the dorsal arms stn, 
and later become connected with the body of the tentorium etn. 
The neuroforamen nf forms a circular opening through which 
the crura cerebri pass, and within it may be seen the tentorial 
tendons by means of which the oesophageal muscles are attached 
to the tentorium. The plate itn is situated between the crura 
cerebri and the mouth, and upon it are inserted certain muscles, 
the median tentorial carnia which it bears being apparently 
developed in connection with this purpose. The body of the 
tentorium serves to protect the suboesophageal ganglion to some 
extent, and the nervous system passes below it (i. e. the body 
of the tentorium) while the gullet passes above it in passing 
backward into the thorax through the large foramen magnum 
or occipital foramen ocf. 
The mouth cavity or pharynx, contains the hypopharynx or 
lingua, hph a tongue-like organ composed of a basal portion, 
or basilingua labelled hi in Fig. 10, and a distal portion of disti- 
lingua dl. The basal portion is strengthened by the basilingual 
sclerites, from which a lingualora ll or slender lora-like sclerite 
extends backward to the oesphagus oes on each side of the base 
of the tongue (hypohparynx), while a lingual tendon It serves 
for the attachment of muscles to the base of the tongue. The 
distal portion of the tongue is strenghtened by the distilingual 
sclerites which send down ventro-mesal arms from each side, 
meeting at the opening of the salivary duct or salivadict sd. 
The salivary glands are paired, and their paired ducts unite to 
form the common salivaduct sd opening at the salivapore which 
is located below the tongue, in the median line, at its base. The 
tongue or hypopharynx is provided with taste organs, as are al- 
so the epipharyngeal areas in the roof of the pharyngeal cavity 
and the regions adjacent to the oesophageal opening, etc. The 
pharyngeal cavity is closed by the labrum and clypeus in front, 
by the labium in the rear, and by the maxillge and mandibles on 
the sides, and it leads into the oesophagus oes of Fig. 10 which 
