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vessel and, like the secondary afferent hyoidean artery, could only be 

 traced about one half the length of the ceratohyal. If it extends far 

 enough to perforate the suspensorial apparatus and, reaching the ex- 

 ternal surface of that apparatus, there give off a mandibular branch, 

 that branch is certainly unimportant as a blood-supplying vessel to 

 the mandible, that function being fulfilled by terminal branches of 

 the external carotid. 



An efferent branchial artery is found in each of the first four 

 branchial arches, and these arteries are not double at their ventral 

 ends, as it will be shown that they are in Salmo and in Amia. The 

 arteries of the first and second arches empty independently into the 

 lateral dorsal aorta of their side, the arteries of the third and fourth 

 arches first uniting to form a common trunk which then empties into 

 the median dorsal aorta. 



The ventral ends of the efferent arteries of the third branchial 

 arches are united by a cross-commissural vessel which passes venti'al 

 to the truncus arteriosus, and from this vessel a single median artery 

 has its origin, this vessel being the median hypobranchial artery of 

 Paeker and Davis's (1899) nomenclature. Running posteriorly this 

 median vessel sends an important branch to muscles ventral to the 

 heart and then continues onward and terminates in the muscles of 

 the latter organ. There is no cross-commissure connecting the ventral 

 ends of the efferent arteries of the first branchial arches, as it will 

 be shown that there is in Gadus and in Amia, and as there is said 

 to be in the Loricati also (Allen, 1905). 



In the angle formed where the efferent artery of the first bran- 

 chial arch joins the lateral dorsal aorta, the external carotid has its 

 origin, the basal portion of this artery being shown, but not named, 

 in Maurer's figure of this fish (Maurer, 1884, Fig. 1, PI. XI). From 

 this external carotid artery a branch is soon sent downward and 

 backward, this branch, after having sent a branch to the muscles of 

 the region, traversing the facialis canal through the hyomandibular 

 with the facialis nerve. Having issued from that canal this branch 

 of the external carotid first continues downward along the outer sur- 

 face of the hyomandibular and then enters the dorsal end of the 

 ceratohyal portion of the hyoidean arch, where it breaks up in the 

 region of the terminal branches of the secondary afferent hyoidean 

 artery, without however forming, so far as could be determined, 

 any connection with the terminal branches of that artery. 



