118 Edward Phelps Allis jr., 



the mandibular aortic arch, which in Amia connects the ophthalmica 

 magna with the internal carotid, is wanting; that the ophthalmicae 

 magnae of opposite sides are connected by a commissure not found 

 in Amia; that the internal carotids of opposite sides anastomose 

 in the median line, as in elasmobranchs; that there is an orbito- 

 nasal arter}', not evident in Atnia; and that Allen shows no artery 

 that can be identified as representing' the ventral portion of the 

 hj'Oidean aortic arch. Allen furthermore does not show any vessel 

 that could in any way represent the hyo-opercularis of my descriptions 

 of Amia; and .yet I found, in all the specimens of the Loricati that 

 I examined, a vessel which, in part at least, would seem to certainly 

 represent that artery. All of the specimens that I examined in 

 this connection were examined by sections, and all of them were 

 small adults and not embryos, one specimen of Lepidoirigla pini 

 having- a length of 63 mm, and hence clearly being an adult fish. 

 The artery, in all these specimens, is small, as it is Amia, and, as 

 in that fish, traverses the trigemino-facialis chamber with the 

 external carotid. It. however, seems to be, in all of the mail-cheeked 

 fishes, a degenerating vessel, and its point of origin from the aorta 

 could not be definitively established excepting in the two Dactjdopteri 

 that were examined. In all the specimens of all the other fishes 

 examined it seemed to arise sometimes from the aorta and sometimes 

 from one or the other of the first three efferent branchial arteries; 

 but the origin could never be positively established. Furthermore, 

 the vessel, in these fishes, branches much more frequently than 

 in Amia, and while it would seem to represent the hyo-opercularis 

 of that fish, it may perhaps simply be a nutritive vessel of some 

 sort. My published statement regarding it (Allis, 1907) is certainly 

 more positive than the facts warrant. 



The orbito-nasal artery of the Loricati is apparently an artery 

 peculiar to teleosts. In the specimens that I have examined it 

 arises from the internal carotid, either slightly before or just as 

 that artery traverses the internal carotid foramen between the 

 prootic and the ascending process of the parasphenoid. The artery 

 then traverses the myodome, and having entered the orbit, passes 

 lateral to the arteria ophthalmica magna, there always coming into 

 verj' close relations with that artery, and in several specimens even 

 perforating its sheath. In one specimen, a small vessel left the 

 orbito-nasal, ran directly to the ophthalmica magna and apparently 

 definitely joined it; but the sections of this specimen were 20 u 



