X Journal of Comparative Neurology. 



nerves seems therefore to have migrated to the third and nasal 

 nerves. 



The interesting problems connected with the ciliary ganglion are 

 discussed quite fully. It is not the same as the mesocephalic gan- 

 glion of Beard in the Elasmobranchs. The nasal nerve of man is 

 identified with the ophthalmicus profundus of Elasmobranchs, and 

 the frontal with the ophthalmicus superficialis trigemini. The author 

 is inclined to regard the ophthalmic, or mesocephalic, ganglion as 

 fused with the Gasserian in man and the rat, for in both of these 

 cases the nasal and frontal nerves from the first arise as branches of 

 the Gasserian ganglion. The ciliary in man is, therefore, a purely 

 sympathetic ganglion. 



It has of late been stated independently by several writers that 

 the third and fourth nerves differ from other motor nerves in that they 

 grow from peripheral ganglia into the brain. That there is a transient 

 ganglion and a centripetal growth in each case seems pretty well estab- 

 lished, but if Dixon's explanation holds, the case is by no means as 

 anomalous as might at first, appear. He assumes, following Miss 

 Piatt, that in each case we have a "cellular nerve" or proton de- 

 veloped from the ganglion to the brain, into which the fibers subse- 

 quently grow centrifugally from the brain. What the significance of 

 this transient cellular proton may be is not made plain. 



Superior Maxillary Division. — Tkis nerve is at first unbranched 

 and is not connected with any ganglion except the Gasserian, from 

 which it grows. 



Inferior Maxillary Division. — This too is unbranched at first and 

 the inferior dental nerve is to be looked upon as the direct continua- 

 tion of the first formed inferior maxillary division of the fifth nerve. 

 All the important branches of the inferior maxillary nerve are repre- 

 sented in the embryo at the beginning of the sixth week. At this 

 time the two accessory ganglia of the inferior maxillary nerve appear 

 nearly simultaneously, and no proof was found that their cells are de- 

 rived directly from the cells of the Gasserian ganglion. Their devel- 

 opment indicates that they must be regarded as typical sympathetic 

 ganglia and in no sense compared to spinal ganglia. 



The development of the connection* of the trigeminal with the 

 seventh and ninth nerves is of great interest. At the fifth week the 

 chorda tympani nerve does not join the lingual, but is connected only 

 with the seventh nerve. In this embryo also the vidian nerve does 

 not yet communicate with the ganglion of Meckel or superior maxil- 

 lary nerve. Both of these nerves are therefore branches of the sev- 



