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branches to the muscles of the cheek, and then continues onward 

 and terminates in the mandible. In Ophiodon, Allen (1905) con- 

 siders the secondary afferent pseudobranchial artery as the direct 

 and primary continuation of the external carotid, the main maxillo- 

 mandibular portion of the artery, as described by me, being considered 

 by him as a facial is-maxillary branch. The facialis portion, or "facial 

 artery" of this so-called facialis-maxillary branch, is the terminal, 

 or mandibular portion of the artery as described by me, but this portion 

 of the artery, in Ophiodon, is not continued onward into the mandible. 

 In Lopholatilus also this branch of the external carotid (hyo-opercularis, 

 Silvester 1904) is said not to be continued into the mandible. 

 I however find it so continued in both Esox and Salmo, as it is 

 also in Polyodon (Allis 1911a) and in Chlamydoselachus (Allis 1911b). 



The arteries in Amia and teleosts can now be summarized and 

 compared, and their possible homologies discussed. 



The afferent mandibular artery — the arteria hyoidea, or hyoidean 

 artery of most descriptions of teleosts and the arteria hyo-mandibularis 

 of Maurer's later descriptions (1888) — appears, in all the fishes here 

 under consideration, as a ventro-anterior prolongation of the efferent 

 artery of the first branchial arch. The artery is generally considered 

 to be the persisting primary aortic vessel of the arch, which vessel 

 has lost its primary connection with the truncus arteriosus and 

 secondarily acquired a connection with the first efferent branchial 

 artery. That this secondary connection is acquired through the per- 

 sisting hyobranchial portion of a longitudinal commissure that primarily 

 connected the ventral ends of all the postmandibular efferent visceral 

 arteries seems evident, and this would suggest that the persisting afferent 

 mandibular artery might be primarily an efferent and not an afferent, 

 or aortic vessel. The artery, in all the fishes here under consideration, 

 runs upward in the hyoidean arch anterior to the ceratohyal and, in 

 all of them excepting only Esox, can be traced to the dorsal (proximal) 

 end of that bone, where it perforates the suspensorial apparatus 

 between the preopercular and the posterior process of the quadrate 

 posteriorly, and the symplectic and the body of the quadrate anteriorly, 

 and so reaches the external surface of the apparatus. There it sends 

 an important branch downward and forward into the mandible, the 

 artery then, in Salmo, Gadus and the Loricati, again perforating the 

 suspensorial apparatus, anterior to the hyomandibular, between that 

 element and the metapterygoid, to enter and supply the pseudobranch. 



