1892.] The Head of an Embryo Amphiuma. 677 
material was none too well preserved, I am not able to say 
how many roots the nerve has, as it comes from the brain. 
Several distinct groups of fibres go from the anterior.angle of 
the medulla to the gasserian ganglion. This latter structure 
is single and shows none of the double character described by 
von Plessin and Rabinowicz’ in Salamandra maculata. Nor 
do my studies of the nerve fibres agree with their accounts of 
the nerves. The Gasserian ganglion is oval in shape. It lies 
in the angle formed by the otic capsule, the processes of the 
trabeculae and the process ascendens of the quadrate. From 
its hinder surface a commissure connects it with the ganglion 
acustico-facialis. From its outer surface arises the maxillaris 
inferior, and from its anterior end, at different levels, the rami 
ophthalmicus superficialis, ophthalmicus profundus and max- 
illaris superior. The maxillaris inferior and the maxillaris 
superior, after leaving the ganglion, pass from the cranial cav- 
ity between the process ascendens of the quadrate and the otic 
capsule. According to von Plessin and Rabinowicz these rami 
are different in cerebral origin in Sal. maculata, but in my sec- 
tion some of the fibres which compose each are easily traced 
to a common origin. Of the distribution of these nerves 
nothing need here be said. 
The two ophthalmici leave the cranial cavity through the 
foramen below the process ascendens of the quadrate. The 
ophthalmicus profundus passes beneath the optic and oculomo- 
torius and breaks up into fibres at the posterior wall of the 
nasal capsule. Fibres from the ganglion of the seventh are 
traced through the gasserian ganglion into the ophthalmicus 
_ superficialis. 
The compound facialis-auditory ganglion is long and nar- 
row. From it arises the palatine branch which goes through 
‘According algae’ authors the Gasserian ganglion consists of two distinct and 
e a ventral principal ganglion and a more dorsal accessory portion. 
The chief ai has its proper medullary root, while the root of the accessory 
ganglion is close by and a little dorsal to the root of the acustico-facialis. From the 
principal ganglion arise two nerves, called respectively mandibularis (== maxillaris 
inferior) and nasalis (= ophthalmicus profundus); from the accessory ganglion arise 
the supramaxillaris superior (= maxillaris superior) and the frontalis (= ophthalmi- 
cus superficialis). 
