30 Journal of Comparative Neurology. 



in different species, this nerve splits into three branches — one 

 for each of the divisions of the median tripartite eye. Passin<T 

 upwards (dorsad) between the mid-gut and the cephahc border 

 of the body these branches pass to the compound eye, which 

 Hes near the dorsal surface of the body. Indeed, this median 

 eye Hes against the shell, vertically above the supra-oesopahgeal 

 ganglion [fig. 2, 9, 100, 420]. 



In Notodronias, according to Wenzel Vavra, there are three 

 optic nerves arising from the apex of the brain [fig. 30]. Here 

 also we find that the three parts of the eye are widely separated 

 [fig. 30]. It does not require a very active imagination to 

 conclude that simultaneously with the divarication of the com- 

 ponent parts of the triune eye there went a longitudinal tripar- 

 tite splitting of the entire optic nerve. 



Antenmdary Nerves. — The paired antennulary nerves arise 

 one from near each lateral surface of the apex of the supra- 

 oesophageal ganglion [fig. 10, 42]. After leaving this gan- 

 glion the nerve passes in a caudally convex curve upwards 

 (dorsad), between the mid-gut and the cephalic border of the 

 body, to the corresponding ganglion. There is no root gan- 

 glion at the base of this nerve. 



Antenfiary Nerves. — Where each circum-oesophageal com- 

 missure leaves the supra-oesophageal ganglion arises an anten- 

 nary nerve [ fig. 3]. This nerve receives its fibres, not only 

 from the brain, but also from a ganglion that extends in a strag- 

 gling manner along the pharyngeal collar [fig. 2, 8]. 



Labial Ncives. — The labial nerve or nerve of the upper 

 lip arises in the cephalic portion of the sub-oesophageal ganglion. 

 Instead of leaving the central nerve chain immediately, this 

 nerve passes upwards ( cephalo-dorsad ) into the pharyngeal col- 

 lar and thence forward (cephalad) to the upper lip [fig. 3, 16, 

 42 ]. There is a large root ganglion at the origin of this nerve 

 [fig. 3]. The labial nerve has two main branches. One 

 branch innervates a pear-shaped sense organ situated in the 

 front part of the body below [ventrad of] the base of the an- 

 tenna, while the other innervates a harp-shaped sense organ 

 located in the lower [ventral] portion of the upper lip [fig. 16]. 



