1890.] the Ciliary or Motor Oculi Ganglion. 



289 



groups of cells lying parallel to or in contact with the motor 

 oculi. 



In some cases ganglionic cells had wandered from the ganglion a 

 considerable distance along the ciliary nerves towards the eyeball. 



Although in sharks the ciliary ganglion often lay in close contact 

 with the motor oculi nerve, no ganglionic cells were ever found 

 either in the trunk of that nerve or on any of its branches. In 

 skates the ganglion was usually more intimately related with the 

 ophthalmicus profundus than the oculo-motor. In all cases the ciliary 

 ganglion had at least two roots, one from the motor oculi, and one or 

 two from the ophthalmicus profundus. In skates the profundus root 

 always proceeded directly from the profundus ganglion, and the pro- 

 fundus ganglion was frequently found to be connected by a com- 

 municating branch with the Gasserian ganglion. 



Both in sharks and skates, in addition to the ciliary nerves from the 

 ciliary ganglion there were ciliary nerves proceeding from the gang- 

 lion and from the trunk of the profundus, and in some cases large 

 ganglionic cells had wandered from the profundus ganglion along the 

 ciliary nerves ; occasionally a few large cells had migrated some dis- 

 tance along the main trunk of the profundus. In all cases the 

 majority of the cells of the ciliary ganglion were only about half the 

 size of the cells of the profundus ganglion. 



In skate embryos (B. batis) under two inches in length no indication 

 of the ciliary ganglion was discovered, and in shark embryos about ten 

 inches in length the ganglion was frequently represented by small 

 groups of cells in the vicinity of the inferior branch of the oculo- 

 motor nerve. In sharks the first steps in the development of the 

 ganglion were not observed, but in skates it was possible to make oafc 

 all the stages. The first indication of the ganglion was in the form 

 of a slender outgrowth from the inferior border of the large ophthal- 

 micus profundus ganglion, which met and blended with fibres from the 

 descending branch of the motor oculi. The outgrowth from the pro- 

 fundus ganglion was crowded with cells ; the fibres from the motor oculi, 

 like its root and trunk, were absolutely destitute of cells. At a some- 

 what later stage the cells had accumulated at the junction of the out- 

 growth from the profundus ganglion with the fibres from the motor 

 oculi. It looked as if the blending of the two sets of fibres had 

 formed a network which resisted the further migration of the gang- 

 lionic cells. In typical cases, at a still later stage, all the ganglionic 

 cells had left the outgrowth from the profundus ganglion to form a 

 rounded mass from which the ciliary nerves took their origin. In 

 some instances some of the fibres which connected the profundus 

 ganglion with the Gasserian seemed to reach and end in the ciliary 

 ganglion. It thus appears that the ciliary ganglion stands in the 

 same relation to one of the cranial nerves (the ophthalmicus pro- 



