36 Dixon—On the Development of the Branches of the Fifth Cranial Nerve in Man. 
whether they grow out in the opposite direction from the Gasserian towards the 
“ciliary” ganglion. They assume, however, that the nerve belongs to the 
‘‘ ciliary ” ganglion, and hence to the third nerve. They further remark that the 
ramus ophthalmicus profundus clearly represents the nasal nerve of mammals—an 
observation which has received confirmation from a large number of more recent 
writers. It must be noted, however, that according to Marshall and Spencer this 
nerve, if it represents the nasal of mammals, passes under the internal rectus 
as well as under the superior rectus and superior oblique muscles in Seyllium 
(p. 29). 
Marshall and Spencer thus separate in Scyllium the nasal nerve from the rest 
of the ophthalmic division, and refer it to a distinct ganglion, which they call 
* ciliary.” 
That they are right in doing this has been borne out by the observations of a 
number of more recent investigators. They only err in so far that they ascribe 
their “ciliary ” ganglion, and with it the ramus profundus, to the third 
nerve. 
Beard* has shown that the ganglion discovered by Marshall and Spencer is not 
the true ciliary ganglion, nor yet the ganglion of the third nerve. The ganglion 
of Marshall and Spencer gives origin to the fibres of the ramus profundus. Beard 
who had formerly followed Marshall and Spencer, and Van Wijhe in calling this 
ganglion “ciliary ” proposes now for it the name ‘ mesocephalic.” He says: ‘'The 
mesocephalic ganglion is the ganglion of a posterior root of a cranial nerve; it 
is the homologue of the Gasserian, facial, or glosso-pharyngeal ganglion. Its only 
nerve at the present time is the ophthalmicus profundus. The ciliary ganglion 
is developed much later than the segmental cranial ganglia, and is not the 
ganglion of a posterior root of a cranial nerve; it probably belongs to the 
sympathetic” (page 575). 
Van Wijhe first clearly demonstrated, according to Beard, that m Elasmo- 
branchs the ganglion on the ramus profundus was the ganglion of a posterior 
nerve-root, unlike Beard however, he retained the term “ciliary,” although 
he knew that it did not represent the ciliary ganglion of the adult, or ganglion 
oculomotorii, as he called it. Beard’s Paper is a very important one, as he makes 
very plain the separation between the ganglion of the ramus profundus and the 
ciliary. He states that what is found in Elasmobranchs is practically reproduced 
in the chick. On the other hand, ‘‘in amphibians, and very probably in all 
mammals, certainly in man, the mesocephalic ganglion is partly fused from 
the start with the Gasserian, and only appears as a blunt process of the latter as 
figured by His” (page 567). 
* « The Ciliary or Motoroculi Ganglion and the Ganglion of the ophthalmicus profundus in Sharks.’ 
Anatomischer Anzeiger, 1887, p. 569. 
’ 
