222 



transmitting the oculomotorius and a large nerve bundle which is 

 doubtless the ramus ophthalmicus profundus, as Van Wijhe and Pol- 

 lard have stated, although I have not as yet controlled this. In 

 the two adult specimens that I have examined in this connection, all 

 five of these foramina are found, four of them perforating the sphe- 

 noid somewhat more than midway between the opticus and trigeminus 

 foramina, while the fifth lies near the hind edge of the sphenoid, or 

 even between that bone and the cartilage posterior to it. This latter 

 foramen is the posterior one of the two that transmit branches of the 

 external jugular, and as the vein that traverses the anterior foramen 

 must be the anterior cerebral vein of my descriptions of Amia (1897) 

 and Scomber (1903), it would seem as if the vein that traverses the 

 posterior foramen must be the encephalic vein of Allen's descriptions 

 of the Loricati, notwithstanding its somewhat different origin from 

 the jugular veins and the somewhat different place in which it pierces 

 the cranial wall. The external jugular vein corresponds, in the basal 

 portion here considered, very closely to the vein ov^ of my descriptions 

 of Amia, the internal jugular corresponding to the vein ov of Amia, 

 which in that fish collects the blood fi'om the choroid gland. 



Having passed the pituitary foramen, the internal carotid and 

 internal jugular continue forward along the dorsal surface of the 

 parasphenoid, that bone here forming part of the floor of the orbit, 

 but, at this point, still lying a considerable distance posterior to the 

 eye ball itself. Having so traversed about one half of the length of 

 the orbit, the artery and vein reach a point immediately ventral to 

 the common point of origin of the recti superior, inferior and ex- 

 ternus, this point lying slightly posterior to the opticus foramen and 

 corresponding to the hind end of the orbit as usually found and de- 

 fined in teleosts; as the general confirmation of the bounding bones 

 of the skeletal orbit makes plainly evident. There the internal carotid 

 gives off' a branch which goes mainly to the maxilla and mandible 

 but which first sends a small branch forward along the floor of the 

 orbit. This branch of the internal carotid would thus seem to be a 

 persisting dorsal remnant of the mandibular aortic arch, the branch 

 sent forward along the floor of the orbit being possibly the ophthal- 

 mica magna here turned to other usage because of the suppression 

 of the choroid gland. They are, at least, shown as those two arteries 

 in the accompanying diagram. 



Slightly anterior to this mandibular artery, the internal carotid 

 turns upward immediately in front of the ligament which gives origin 

 to the three recti muscles above referred to, and perforating the 



