— 194 — 



the latter nerve being accompanied by certain meningeal vessels. The foramen rotundum is said by 

 Thane (Quain, vol. II, pt. I) to liave been separated off from the sphenoidal fissure by the growth 

 of bone around the nerve, the foramen ovale being similarly cut off from the foramen lacerum. The 

 foramen lacerum is an aperture between the apex of the petrous portion of the temporal bone and 

 the body and great wing of the sphenoid, and would seem to correspond to the trigeminus foramen 

 of Amia, though it may include some part also of the trigeminus opening of the trigemino-facialis 

 Chamber of teleosts. Comparison with fishes would thus indicate that the foramen ovale and the 

 foramen rotundum must both be parts of the foramen lacerum, instead of being respectively parts 

 of that foramen and of the sphenoidal fissure. The foramen spinosum of man, which perforates the 

 great wing of the sphenoid and transmits the large middle meningeal vessels, must have its homologue 

 in one or both of those perforations of the alisphenoid that, in teleosts, transmits branches of the 

 external carotid artery and orbito-nasal vein. 



The foramina related to the nervus facialis are not so readily homologized. The facialis foramen 

 and the facialis opening of the trigemino-facialis Chamber of teleosts must together represent parts 

 of the Aqueduct of Fallopius of man, but apparently not the whole of it, for the lower part of the 

 aqueduct is said by Thane to be included between the outer surface of the periotic and the tympanic 

 plate, and until this latter plate is identified in fishes, the homologue of the stylo-mastoid foramen 

 can not be determined. The hiatus Fallopii, which leads from the Aqueduct of Fallopius to the 

 depression on the petrous that lodges the Gasserian ganglion, is evidently that part of the trigemino- 

 facialis Chamber that lies between the facialis and trigeminus foramina; the Vidian canal being what 

 I have described as the palatine canal in Amia, a canal that lies between the parasphenoid (pterygoid 

 of man, Gaupp, '05) and the cartilaginous basis cranii of that fish. In teleosts this canal is absent 

 because of the suppression of the cartilage in this region. The internal jugular vein does not, in man, 

 lssue with the nervus facialis, issuing instead through the jugular foramen which transmits also the 

 glossopharyngeus, vagus and spinal accessory nerves. The internal carotid canal, which, in man, 

 tra verses the petrous part of the temporal bone, seems not to be the exact homologue of the internal 

 carotid foramen of fishes, this latter foramen lying between the proötic and parasphenoid instead of 

 traversing the former bone. But as the artery then traverses the cavernous sinus in man and the myo- 

 dome in fishes the canal of the one must be in large part the homologue of the foramen of the other. 



Regarding the bones of the region, the posterior clinoid wall is represented in the mesial pro- 

 cesses of the proötics of Amia, the anterior clinoid wall being represented either by the basisphenoid 

 of teleosts, by the prepituitary part of the mesial processes of the proötics, or by those bones fused 

 to form a single element. The spicula of bone that, in man, sometimes unite the anterior and posterior 

 clinoid processes are then those parts of the mesial processes of the proötics of teleosts that lie lateral 

 to the pituitary opening. The parasphenoid leg of the alisphenoid of teleosts is the great wing of 

 the sphenoid bone of man, the basisphenoid leg of the bone of fishes apparently being suppressed 

 by an invading growth of the orbitosphenoid which forms the small wing of the sphenoid of man. 

 The basisphenoid of fishes, if it persists as a sepaTate bone, is the presphenoid of man, but, as just 

 above stated, that bone of man would seem to at least include the prepituitary parts of the mesial 

 processes of the proötics of teleosts. The basisphenoid of man, if it is found in fishes, would seem to 

 be represented in a part of the proötic, but it is perhaps possible that the median ossification in the 

 dorsal surface of the proötic bridge of my one specimen of Gadus morrhua, described below, may 

 be the homologue of that bone. 



