EYE-MUSCLE NERVES IN NECTURUS 161 



nerves and passing forward in the sheath of these nerves comes to 

 lie on the ventral face of the Gasserian ganglion of the trigeminal 

 nerve. Here the abducent nerve lies in the connective tissue 

 sheath of the Gasserian ganglion, no interchange of fibers ever 

 having been observed between the abducent nerve and any part 

 of the trigeminal. Passing now slightly ventrad, the abducent 

 nerve soon enters the temporal muscle which at this point takes 

 its origin from the lateral surface of the trabecular cartilage. 

 Running in this muscle just ventro-laterad to the r. ophthalmicus 

 profundus V, the abducent nerve reaches the common origin of 

 the recti muscles and then swings laterad to enter the ventro- 

 caudal face of the lateral rectus muscle (figs. 4, 5, 6 and 7) . 



In four of the eyes dissected, a small twig has been observed 

 running to the sheath of the optic nerve from the abducent nerve 

 as it breaks up in the lateral rectus muscle (fig. 5) . In one case 

 this was a large twig of five or six fibers, in the others only two or 

 three fibers were concerned. 



Nn. ciliares 



There is constantly present a branch of the r. ophthalmicus 

 profundus V, which enters the sheath of the optic nerve (figs. 

 5 and 7). This fascicle, containing usually about ten fibers, leaves 

 the lateral border of the r. ophthalmicus profundus V just before 

 the orbit is reached, and running dorsal to the lateral rectus 

 muscle, applies itself to the dorso-caudal face of the sheath, of 

 the optic nerve. Many of the fibers of this twig reach the eye- 

 ball. 



Mention has already been made, in the descriptions of the 

 oculomotor and abducent nerves, of twigs from these nerves 

 entering the bulbar fascia and the sheath of the optic nerve. 

 Some of these twigs reach the eyeball. 



In none of the specimens examined has there been found any 

 group of cells corresponding to the ciliary ganglion. The condi- 

 tion in Necturus may be similar to that in Squalus acanthias as 

 reported by Dr. H. D. Senior at the meeting of the American 

 Association of Anatomists, December, 1912. Here no ciliary 

 ganglion is said to exist, the motor ciliary nerves containing, 



