MYODOME AND TRIGEMINO-FACIALIS CHAMBER 243 
said to be formed by the anterior, external wall of the bulla 
acustica, and it lodges the extracranial semilunar and ciliaris 
ganglia. The posterior portion of its roof is evidently formed 
_ bya horizontal plate of cartilage shown, in the figures given 
by him (i. c., figs. 7 to 9, Pl. 1), lying ventral to the hypophysis, 
and which must accordingly represent the prootic bridge. In 
a figure of a transverse section in the postfacialis region a ven- 
trally projecting process is shown at each lateral edge of this 
prootic bridge, and its ventral portion has apparently been cut 
off in the figure. These two processes certainly represent 
transverse sections of ventral processes of the prootics, sim- 
ilar to those found in other Teleostei, and they must form the 
lateral walls of the so-called extracranial myodome. Each 
process lies mesial to the foramen faciale of its side, and lateral 
to this foramen and also lateral to the foramen trigeminum 
there is a slight ridge of cartilage which must represent a dorsal 
portion of the lateral wall of the pars jugularis of a trigemino- 
facialis chamber. The ganglion trigeminum thus probably les 
in the orbital opening of this chamber and not in the dorso- 
lateral corner of the myodome, as Handrick concluded. The 
basis cranil is perforated by a so-called ‘Pituitargrube,’ which 
is said to extend from the foramen trochleare nearly to the fo- 
ramen trigeminum, is shown closed by a membrane which is per- 
forated by the nervi optici, and extends posteriorly to the an- 
terior edge of the prootic bridge. This so-called pituitary fossa_ 
is thus simply a perforation of the primitive cranial wall which 
has been formed by the fusion of the pituitary opening of the 
brain case with the foramina optici. 
Supino (’01), in a work I did not have at my disposal when 
my paper on the mail-cheeked fishes was sent to press, finds 
several bones developed in relation to the neurocranium of this 
fish, two of them being the prootics and one the parasphenoid. 
This latter bone must evidently lie ventral to the myodome, 
and in a figure giving a ventral view of the entire neurocran- 
ium, extensive ventral processes of the prootics are shown which 
must form the lateral walls of the myodome. The foramina 
for the nervi trigeminus and facialis are said to perforate the 
