OPHTHALMIC NERVES OF GNATHOSTOME FISHES 73 



gemini in these latter vertebrates, which is in accord with Pinkus's 

 ('94) conclusion that the presence of this nerve in the Amphibia 

 is very doubtful, and with Norris's statement ('13, p. 292) that, 

 in Siren lacertina: ''It is questionable whether any general cu- 

 taneous fiber should be considered as a constituent part of the 

 dorsal, or supraorbital division [of the truncus supraorbitalis] of 

 Siren." The ramus ophthalmicus profundi of Polypterus thus 

 quite certainly being the homologue of the so-called ophthalmicus 

 trigemini of man, the introduction of a proper and uniform ter- 

 minology becomes a somewhat radical proceeding, for it evi- 

 dently requires a renaming of the nerve in man. 



The conditions in those fishes, other than Polypterus, in which 

 either a ramus ophthalmicus profundus trigemini, or a portio 

 ophthalmici profundi, has been described, may now be consid- 

 ered, and I have, furthermore, examined the conditions in Gas- 

 terosteus, Cottus, and Clinocottus, in which fishes there is an 

 anterior portion of the ascending process of the parasphenoid 

 that occupies the position of the pedicel of the alisphenoid of 

 Amia. The reason for examining these latter fishes was the con- 

 viction that, if there were a portio ophthalmici profundi, it 

 would lie anterior to the above-mentioned anterior process of 

 the parasphenoid, for that is the relation that the radix profundi 

 of these fishes has to that process; and, conversely, if no branch 

 of the profundus, sent to the superficialis, were found in that posi- 

 tion, it would be, in my opinion, conclusive evidence that the 

 portio ophthalmici profundi was wanting in these fishes, and 

 hence presumptive evidence that it was also wanting in those 

 of the Teleostei in which the process is not found. 



In Protopterus, Pinkus ('94) describes a ramus ophthalmicus 

 profundus trigemini, but no portio ophthalmici profundi. The 

 first three branches of the ophthalmicus profundus are small, and, 

 running forward dorsal to the nervi oculomotorius and troch- 

 learis, become associated with a ramus ophthalmicus superficialis 

 facialis. The ophthalmicus profundus then separates into two 

 nearly equal portions, one of which is shown, in the figure given, 

 running forward dorsal to both divisions of the nervus oculomo- 

 torius, and the other ventral to them, the dorsal branch then 



