308 TUNICA VASCULOSA, BY PROF. A. iWANOFF. 



(nervi ciliares longi) two, or more rarely three in number, 

 proceed from the ramus naso-ciliaris trigemini ; the short set 

 (nervi ciliares breves), fourteen to eighteen in number, proceed 

 from the ganglion ciliare. Both sets perforate the sclerotic 

 near the entrance of the optic nerve, and having gained the 

 interior of the eye, run upon the external surface of the 

 choroid. After they have given off a considerable number of 

 branches to the posterior portion of the membrane, they pass 

 forward to the ciliary muscle, on which, dividing dichotomously, 

 they form a close plexus. H. Miiller* found ganglion cells in 

 the angles of the first divisions of these nerves, with a dia- 

 meter of 0'0016 0'025 of a millimeter, and containing two or 

 three nuclei. In the deep layers of this plexus, lying in the 

 interior of the muscle, we find, in addition, nodal swellings, 

 closely resembling bipolar cells. 



The peculiarity of the structure of the nerve plexus in the 

 posterior portion of the choroid is, that the ciliary nerves, im- 

 mediately after their exit from the sclerotic, and as they run 

 forwards to the ciliary muscle, give off lateral branches, which 

 are composed partly of dark-edged and partly of pale nerve 

 fibres. These lateral branches, after repeated divisions and 

 anastomoses, form a plexus lying between the vessels and the 

 sclerotic. From this plexus delicate filaments may be traced 

 to the arteries, in the smooth muscular fibres of which they 

 appear to terminate. Ganglion cells are also found in this 

 plexus occupying the points of intersection. True ganglia 

 likewise occur in the trunks of the ciliary nerves. 



It is worthy of note that both the development of the pos- 

 terior nerve-plexus, as well as the number of ganglion cells to 

 be met with in this part, undergoes considerable individual 

 variation, and it is also to be remarked that these variations 

 stand in close relation to the development of the smooth mus- 

 cular fibres in the posterior portion of the choroid. 



5. The stroma of the choroid is formed of a close plexus of 

 branched fibres, in the interspaces of which, especially of the 

 outer layers, considerable numbers of stellate pigment cells are 

 imbedded. 



* Verliandlungen der phys. med. Gesellschaft in Wilrzburg, Band x., p. 108. 



