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This facialis branch of the external carotid of Esox is manifestly 

 the horaologue of the facialis branch of the hyo-opercularis of my 

 descriptions of Amia (Allis, 1900), and it must accordingly, as in 

 that fish, be a persisting dorsal portion of the efferent hyoidean artery. 

 It is the only arterial vessel that perforates the hyomandibular, and 

 it certainly has no connection whatever with the pseudobranch. 

 Furthermore, as it is a hyoidean vessel, it can not be a persisting 

 dorsal portion of the so-called arteria hyoidea of Maurer's descriptions 

 of Esox, for although when writing those descriptions Maurer con- 

 sidered the so-called arteria hyoidea as a hyoidean vessel it is in 

 reality a mandibular one, as Maurer himself later concluded. The 

 only explanation of Maurer's statement that the arteria hyoidea of 

 his descriptions of embryos of this fish perforates the hyomandibular 

 is accordingly to assume that, in his sections, he mistook some portion 

 of the palato-quadrate arch for a part of the hyomandibular; the 

 artery in embryos of Esox quite certainly perforating the suspensorial 

 apparatus anterior to the hyomandibular, between that element and 

 the metapterygoid or quadrate, as it will be shown that it does in the 

 adults of both Salmo and Gradus. 



The external carotid, after giving off the facialis branch above 

 described, sends a branch to accompany the ophthalmicus nerves. 

 It then runs forward dorso-mesial to the dorsal end of the pseudo- 

 branch, at some distance from it, and has, in my specimen, no con- 

 nection whatever with that organ. It does not traverse a trigemino- 

 facialis chamber, as it does in the Loricati and in Amia, and yet 

 that chamber is apparently present in the skull. Running forward 

 and downward the artery passes over the dorso-mesial edge of the 

 palato-quadrate, onto the external surface of that apparatus, where it 

 sends branches to the muscles and tissues of the region and then 

 enters and terminates in the mandible. 



The lateral dorsal aorta, after giving off its external carotid 

 branch, becomes the internal carotid, which artery runs forward along 

 the lateral surface of the skull and having given off, in my specimen, 

 one large branch, perforates the base of the ascending process of the 

 parasphenoid and enters the myodome. There it meets and fuses 

 with its fellow of the opposite side to form a single median artery 

 which turns upward, perforates the roof of the myodome, and enters 

 the cranial cavity. There it immediately separates into two parts, 

 one on either side, each of these parts again separating into anterior 



