270 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



foramen into the eye muscle canal. The two bundles 

 separate in front, but for a time the union is so close that 

 they could not be satisfactorily analysed. However, most 

 of the profundus fibres proximal to the ciliary ganglion 

 separate out as the Ramus ciliaris longus (cil. I.), but a 

 few of them accompany the sympathetic to the ciliary 

 ganglion (cil. g.) as its Radix longa (rx. I.). The R. 

 ciliaris longus leaves the eye muscle canal in front and 

 accompanies the right rectus superior muscle to the eye, 

 which it enters from above. A true Ramus ophthalmicus 

 profundus is therefore absent in the Plaice. 



On the left side the profundus nerve only separates 

 from the root of the trigeminus just before the latter 

 reaches the Grasserian ganglion. The only other differ- 

 ences between the two sides are in matters of detail 

 (cp. the description of the sympathetic). 



The only other Teleost which is said to possess a 

 separate profundus nerve and ganglion is Trigla, in 

 which, according to Stannius, it is in exactly the same 

 condition as in the Plaice, except that it leaves the skull 

 cavity by a special foramen. A vestigial profundus nerve 

 is also described by Herrick in Menidia. Its occurrence 

 in the Plaice in the form described above is therefore of 

 exceptional interest. Stannius missed it altogether in the 

 Plaice, and hence his statement that the v.-vii. complexes 

 of Trigla and Pleuronectes only differ in this respect is 

 inaccurate. 



2. Ramus ophthalmicus superficialis (r. oph. sup. v.). 

 — Arises from the narrowed anterior extremity of the 

 Grasserian ganglion, and constitutes the trigeminal portion 

 of the Truncus supraorbitalis. It accompanies the nerve 

 of the same name from the facial for a considerable dis- 

 tance, being at different places more or less intermingled 

 with it. In front, however, it separates from the facial 



