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the dorsal ends of the premandibular and mandibular aortic arches, 
instead of, as in Amia and selachians, at a point that lies between 
the mandibular and hyoidean arches. As in Amia, Polyodon and 
selachians, there is no arteria orbito-nasalis in Lepidosteus, and, as 
also in those fishes, there is a small branch, here quite rudimentary, 
of the arteria cerebralis anterior which runs forward with the nervus 
olfactorius and after being almost completely pinched off again begins 
and running forward falls into a branch of the carotis externa that 
supplies the nasal sac. 
In each of these three ganoids there is an arteria palatina similar 
to that found in Ceratodus, this artery not being found as such, so 
far as I know, in either selachians, teleosts or Polypterus. 
The arteria temporalis of GretL’s descriptions arises from the 
hyoidean aortic arch near its dorsal end, this aortic arch being called 
by GREIL, in the later stages described by him, the arteria opercularis. 
This arteria temporalis traverses what I have shown to be the trige- 
mino-facialis chamber of the fish (Allis, 1914b), and it is said by GREIL 
to supply the temporalis and masseter muscles. It, accordingly, in 
its origin, course and distribution so closely resembles the carotis 
externa of my descriptions of other fishes that it is certainly the 
homologue of the basal portion, at least, of that artery of those fishes. 
This external carotid artery of my descriptions is not however the 
carotis externa of GREIL’s descriptions of Ceratodus, the latter artery 
being simply a branch sent to the mandible from the ventral end of 
the mandibular aortic arch and corresponding to the mandibular artery 
of ALLEN’s (1905) and my own descriptions of teleosts. The arteria 
temporalis of GrEIL’s descriptions of Ceratodus is apparently the 
posterior (external) carotid of KeLLıcorr’s (1905) descriptions of the 
same fish, but it has not at all the origin ascribed to it by the latter 
author. According to KELLIcoTT, “The posterior (external) carotid 
artery, which supplies the orbit and the anterior end of the head, 
takes its origin from the first epibranchial artery, so that it appears 
as the forward prolongation of the lateral dorsal aorta.” It is first 
shown by KErLıcorr in a diagram showing the arteries in an embryo 
of stage 48, and it there appears as a small budding vessel at the 
anterior end of the post-glossopharyngeal portion of the lateral dorsal 
aorta; and KELLICOTT says of it that it “does not represent a carotid 
artery comparable with that of any other form yet described”. KELLI- 
cotr also shows, in his figures, the mandibular aortic arch as wholly 
