206 EDWARD PHELPS ALLIS, JUN. 



nerves (p. 89). The ramus ophtliahiiiciis profundus is said 

 by him to be of a totally different nature from either of these 

 superficial ophthalmic nerves, and is said to be definitely 

 characterised by its own particular course and position, from 

 which, in his opinion, it never shifts. This opinion, definitely 

 and succinctly stated, seems to have since been either entirely 

 overlooked, or, perhaps, regarded as not worthy even of con- 

 sideration. 



Van Wijlie (66) confirmed Marshall's conclusion that the 

 portio major and portio minor of Schwalbe belonged, respec- 

 tively, to the facial and trigeminal nerves, and he moreover 

 found in stages K and L of embryos of Scyllium and Pris- 

 tiurus, what he considers as a third component, or portio, of 

 the superficial ophthalmic nerve. It is said by him to arise 

 from his ciliary (profundus) ganglion, and, because of its 

 origin and distribution, he calls it the portio ophthalmici pro- 

 fundi of the ramus ophthalmicus superficialis. This portio 

 profundi is said (p. 21) to abort in slightly older stages of 

 Scyllium and Pristiurus, but in Polypterus and Lepidosteus it 

 is said to persist throughout life. It is fully described by 

 him, in these latter fishes, in another work (65) . In this 

 latter work (p. 275) van Wijhe also identifies and describes, 

 in the adult Lepidosteus, the other two portiones (portio tri- 

 gemini and portio facialis) described by him in the superficial 

 ophthalmic nerves of embryos of Scyllium and Pristiurus. In 

 the adult Polypterus, his descriptions, in the same work, lead 

 one to infer that he found all three jDortiones in that fish also, 

 but the reference is not clear, and Pollard (51, p. 395), 

 somewhat later, could not definitely establish the existence of 

 a portio trigemini. In Polypterus both van Wijhe and 

 Pollard describe a ramus ophthalmicus profundus which is 

 said to have the usual selachian relations to the rectus 

 superior and obliquus superior muscles, but not to the rectus 

 internus, the nerve lying dorsal, instead of ventral, to that 

 muscle, the internus of Polypterus, like that of Amia and 

 teleosts, hence perhaps not being the homologne of the simi- 

 larly named muscle in selachians. 



