310 "Journal of Conipnj'ntivr Neurology and PsychoJoe^\. 



Fig. 3. — Dissection of the roof of the mouth of an adult dogfish. X 1%. 

 On the left of the figure are shown the incisions necessary for tlie transection 

 of the olfactory crura and the niaxillaris-niandibularis V trunk in the living 

 fish, while on the right are seen the relations of the various nerves and 

 blood vessels of tlie roof of the mouth, as revealed by the dissection of a 

 dead specimen. 



1. Incision through the cartilage for section of the olfactory crura (C) ; 

 2, incision made in cutting the maxillaris-mandibulai'is trunk (3) ; 3, maxil- 

 laris-mandibularis Y. trunk, includes also the buccalis VII; 4, external 

 carotid artery which should be avoided in cutting the nerve; 5, everted 

 nuicous membrane of the roof of the mouth ; A. R., anterior rectus muscle ; 

 B.. olfactory bulb ; hue. VII. ramus buccalis facialis ; C. olfactory crus ; 

 V. VII., ramus from the trigeniino-facial complex to the truncus hyomandi- 

 bularis. probably general cutaneous; cxt. car. it., external carotid artery; 

 G., Gasserian ganglion; g., geniculate ganglion; 11., cerebral hemisphere; 

 hyoid. a., hyoidean artery; hyomand. VII, truncus hyomandibularis facialis; 

 int. car. a., internal carotid artery; /. O., inferior oblique muscle; /. R.. in- 

 ferior rectus muscle; Maud. ]'., ramus mandibularis trigemini ; Max. V., 

 ranms maxillaris trigemini; Olf. cap., olfactory capsule; Optic, optic nerve; 

 pal. VII, ramus palatinus facialis; pretr. VII, ramus pretrematicus facialis; 

 Prof, v., ramus ophthalmicus profundus trigemini. 



To perform the operations the mouth is pried open, the mucosa is re- 

 tiected and the incisions made directly, care'being taken to avoid the carotid 

 arteries, both internal and external, and the hyoidean. It is necessary to 

 reflect the mucosa, otherwise the location of the blood vessels cannot be 

 determined. 



