60 Drxon—On the Development of the Branches of the Fifth Cranial Nerve in Man. 
cartilage, but then leaving the cartilage it turns more forwards, towards the 
surface of the face below the mouth cleft. The length of inferior dental is 
1-6 mm. 
The mylo-hyoid branch (fig. 17, Plate IT.) is a long slender nerve, which takes 
origin from the inferior dental close to the origin of the latter. The nerve at first 
passes almost vertically downwards, on the outer side of Meckel’s cartilage, and 
then, turning inwards beneath the cartilage, it reaches almost to the middle line. 
The length of mylo-hyoid nerve is 1:2 mm. 
The lingual nerve arising at the same point as the inferior dental, is soon 
separated from the latter by the inner end of Meckel’s cartilage. The course of 
the lingual is horizontally forwards, and inwards. Just behind the inner end of 
Meckel’s cartilage the nerve enters the submaxillary ganglion; a few of the fibres 
passing through the ganglion can be traced a short distance into the tongue. 
Length of lingual nerve is 1:0 mm. The length of the inferior maxillary nerve to 
its division into lingual and inferior dental branches, is 0-4 mm, 
The chorda tympani nerve (figs. 17 & 18, Plate II.) is a long, slender, but easily 
traced nerve, which passes almost vertically upwards from the facial, joiming the 
lingual finally, by turning a little forwards. The nerve is placed close to the outer 
side of the developing Eustachian tube, and is separated from the external auditory 
pit by a considerable interval, in which are seen the developing cartilages of the 
middle ear. 
The sub-maxillary ganglion, into which we have seen the fibres of the lingual 
nerve pass, is very well defined, and lies between Wharton’s duct and the inner 
end of Meckel’s cartilage. 
The otic ganglion is placed to the inner side of the anterior part of the Gas- 
serian ganglion. It is smaller than Meckel’s ganglion, and its cells are more 
closely packed together. The Vidian nerve, on its way to Meckel’s ganglion, 
passes behind, and to the inner side of, the otic ganglion. A fine branch from the 
petrous ganglion of the glosso-pharyngeal, can be traced into the lower and posterior 
part of the otic ganglion (fig. 18, Plate II.). This latter nerve, which represents 
the nerve of Jacobson, has an almost vertical course, and passes close to the point, 
where the Vidian nerve takes origin from the geniculate ganglion of the facial 
nerve. Part of the otic ganglion passes upwards and lies inside the developing 
cranium. At another point the otic and Meckel’s ganglion are connected by a 
narrow neck of cells. 
C. R.—Inferior dental ; oe Gimme 
Mylo-hyoid branch 5 = SY) ran. 
Auriculo-temporal . | = 0:8imm: 
Lingual 3 ; ale Okmm«, 
Long buccal . . . =0°8 mm. 
