154 KDWAED I'HIiLPS ALLIS, JUN. 



its surface pores in, and postei-ioi' to, tlie ventral one of the 

 two bends of tlie supra-orbital canal immediately in front of 

 the eye. The organs of this latter sub-group of ampullae, and 

 also those of the other, more anterior sub-group of the super- 

 ficial ophthalmic ampuUte, are innervated by the deeper one 

 of the two ampuUary branches above referred to. This branch, 

 running forward dorsally and mesially, reaches a position 

 dorso-mesial to the base of the dorso-lateral rostral bar of 

 cartilage, and then, sinking deeper, comes to lie mesial to 

 the bar, where it breaks up and supplies the organs of its two 

 sub-groups of ampullas. 



In that part of the course of the main ophthalmic nerve 

 where these two ampullary branches are given off the lateral 

 canal fibres of the nerve have been gradually collecting in 

 two regions — a dorsal and a veuti'al one. The dorsal fibres 

 soon separate as a separate branch, and from it ten or more 

 branches are given off, some of them arising from the main 

 nerve, from the bundle of fibres destined to form the branch, 

 but before these fibres have entirely separated as a sepai"ate 

 branch from the main nerve. Branching", these several lateral 

 sensory branches supply organs 85 to 58 supra-orbital, all of 

 which lie proximal to the point where the canal anastomoses 

 with the anterior end of the infra-orbital canal, the main 

 branch ending in two branches which supply, the one organs 

 37 and 38, and the other organs 39 and 40. Organs 38 and 

 39 lie one directly dorsal to the other in the anterior bend 

 of the canal, where it passes upward from the ventral to the 

 dorsal surface of the snout. A general sensory nerve, derived 

 from the main nerve, accompanies this lateral nerve, and be- 

 yond its anterior end breaks np into a number of terminal, 

 general sensory branches. 



The remaining, ventral, and larger part of the main 

 ophthalmic nerve contains the lateral sensory fibres destined 

 to organs 17 to 34 supra-orbital, the ampullary fibres destined 

 to the deep ophthalmic group of ampullge, and certain general 

 sensory fibres destined mainly to supply the prenasal parts of 

 the snout. Organs 17 to 34 all lie in the subrostral part of 



