224 NERVE COMPONENTS OF BONY FISHES. 



There is thus formed a long, narrow ganglion made up 

 wholly or nearly so of large cells like those of the Gas- 

 serian ganglion, which runs out along the radix longa and 

 reaches from the Gasserian ganglion nearly to the ciliary 

 ganglion. On this side the radix breva is much longer 

 than on the left side and it arises from the undivided 

 trunk of the oculomotor nerve. 



Contrary to the statement of Stannius, the fibres of the 

 radix brevis are exclusively of fine calibre, arising from a 

 fascicle of fine fibres on the lateral side of the III nerve. 



Distally of the ciliary ganglion the ramus ciliaris brevis 

 lies laterally of all of the branches of the oculomotorius, 

 ventrally of the m. rectus superior and dorsally of the m. 

 rectus inferior and rectus internus. Opposite the optic 

 chiasm it begins to turn ventrad and maintains this 

 course, running under the optic nerve and above the m, 

 rectus inferior until under the insertion of the latter 

 muscle it penetrates the sclerotic and finally enters the 

 iris at its extreme ventral point, almost diametricallj^ 

 opposite the entrance of the ramus ciliaris longus. 



The ramus ciliaris longus {cil. I.) contains some fine 

 fibres with almost as many very coarse and heavily mye- 

 linated ones. It follows the course of a small blood vessel 

 ventrally of and parallel with the supra-orbital trunk and 

 dorsally and somewhat laterally of the m. rectus superior. 

 Dorsally of the eye it receives the anastomosing nerve 

 from the second branch of the supra-orbital trunk. Then, 

 without giving off any obvious branches, it penetrates the 

 sclerotic and enters the iris somewhat caudad and laterad 

 of the insertion of the m. rectus superior. 



The arrangements of the ciliary nerves vary exceed- 

 ingly in different fishes. For the details see Stannius 

 (*49, p. 38) andBaudedot ('83, p. 123). The ramus ciliaris 



