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of which will be later discussed, being considered by Parker as the 

 dorsal end of his hyoidean (afferent mandibular) artery and by 

 BouLENGER as the persisting efferent artery of the hyoidean arch. 



The ophthalmica magna, or efferent pseudobranchial artery, arises 

 from the pseudobranch, runs upward and forward internal to the 

 orbito-nasal artery, is there connected by transverse commissure with 

 its fellow of the opposite side, and then turns outward to enter the 

 eye-ball and supply the choroid. The transverse commissure con- 

 necting the two ophthalmicae magnae passes across the anterior edge 

 of the ascending process of the parasphenoid, without perforating 

 that bone, and there lies on the dorsal surface of the body of the 

 parasphenoid, at the extreme hind end of the orbit, traversing what 

 I have shown (Allis, 1910) to be the but slightly developed myodome 

 of the fish. It there lies immediately anterior to the anterior end of 

 the circulus cephalicus, almost in contact with it. 



The external carotid arises from the lateral dorsal aorta (circulus 

 cephalicus) immediately posterior to the point where that artery is 

 joined by the dorsal end of the efferent artery of the first branchial 

 arch. Running downward and forward it soon gives off three branches 

 arising not far one from the other. One of these branches runs back- 

 ward and supplies the adductor hyomandibularis muscle, a second 

 runs forward and separates into two portions one of which accompanies 

 the ophthalmicus and the other the mandibularis branch of the nervus 

 trigeminus, while the third runs downward through the facialis canal 

 in the hyomandibular, accompanying the nervus facialis. The artery 

 itself then continues downward and forward around the anterior edge 

 of the hyomandibular onto the external surface of the palato-quadrate, 

 and is there distributed to the muscles and tissues of the region, no 

 terminal portion of it being extended into the mandible. 



Posterior to the second efferent branchial artery two small dorsal 

 branchial-muscle arteries have their origin from the lateral dorsal aorta. 



Anterior to the first efferent branchial artery, at a distance from 

 it about equal to the distance between the first and second efferent 

 branchial arteries, a small branch, already referred to, arises from the 

 lateral dorsal aorta. This branch is the one called by MtjLLER, in his 

 descriptions of his plates, "Anastomose derselben [Arterie der Neben- 

 kieme von der Arteria hyoideo-opercularis] mit einem Ast des Circu- 

 lus cephalicus". It runs downward and joins the afferent mandibular 

 artery shortly before that artery enters the pseudobranch, and although 



