MUSTELUS L^VIS. IS*? 



detached and extra-cranial portion of the profundus ganglion. 

 That they represent the entire profundus ganglion seems im- 

 probable, though they occupy exactly the position in which 

 that ganglion would naturally be looked for. That the cells 

 represent one of the two sympathetic ganglia described by 

 Onodi (46) in the adult Mustelus, I greatly doubt; but I 

 find nothing that corresponds to those ganglia, and I cannot 

 even determine, from his descriptions, where they should be 

 looked for. 



The branch that arises from the profundus at the place 

 where the small ganglion is found runs at first backward and 

 but slightly outward along the dorsal edge of the inferior 

 branch of the oculomotorins, here passing with the latter 

 nerve across the anterior edge, and then backward along the 

 dorso-lateral surface of the rectus inferior. While the two 

 nerves are in this latter position the branch of the profundus 

 leaves the oculomotorius, and running outward and backward 

 reaches an outer membranous envelope of the eyeball. In 

 or against this membrane it runs backward and separates 

 into two parts, both of which can be traced backward and 

 outward to the posterior surface of the ej^eball, where, still 

 in or against the membrane, they lie against the antero- 

 lateral surface of the rectus externus, between that muscle 

 and the sclerotic. The dorsal and smaller branch of the 

 nei've here gradually disappears in the membraue, and quite 

 certainly never pierces the sclerotic. The other and larger 

 branch continues further outward around the eyeball, and 

 quite probably pierces the sclerotic, though this could not be 

 definitely established, the sections here being imperfect. 

 This nerve, in its origin and in its relation to the oculomo- 

 torius, corresponds exactly to the posterior ciliai*y nerve, or 

 ciliaris longus, of Schwalbe's descriptions, and Schwalbe says 

 that his nerve pierced the sclerotic. Tiesing says that the 

 oculomotorius, as it passes over the eye-stalk, gives off a 

 delicate ciliary nerve, which unites with a branch of the pro- 

 fundus and goes to the bulbus. The conditions that I find 

 differ somewhat from those described by either of these 



