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The Branchial, Pseudobranchial and Carotid arteries 

 in Baja radiata. 



By Edward Phelps Allis, jr., Menton. 



With 2 figures. 



The branchial, pseudobranchial and carotid arteries of the adult 

 ray have been quite fully described and figured by Joseph Hyrtl 

 (1858) in Torpedo narke and Eaja clavata and by T. J. Parker 

 (1884) in Eaja nasuta, and Parker and Davis (1899) have described 

 and figured the ventral portions of the efferent branchial arteries 

 and the hypobranchial and coronary arteries in Eaja erinacea; but 

 in no one of these several works is the mandibular artery, in both 

 its dorsal and ventral portions, identified as such, or properly de- 

 scribed and figured. I have accordingly had dissections made, by 

 my assistant Mr. John Henry, of two specimens of Eaja radiata 

 which I had, preserved in alcohol, in my laboratory here, and the 

 arteries as there found are here described. 



In Eaja radiata, as in both Eaja nasuta and Eaja erinacea, 

 the afferent arteries to the hyoidean and first branchial arches arise 

 together, as a long and single trunk, from the anterior end of the 

 truncus arteriosus, the afferent arteries to the second, third and 

 fourth branchial arteries arising as a common trunk from near the 

 hind end of the truncus. 



Both anterior and posterior efferent arteries are found in each 

 of the first four branchial arches, and a posterior efferent artery, 

 alone, in the hyoidean arch. The two arteries in each branchial 

 arch are connected by a single intermediate commissure, that com- 

 missure lying internal to the afferent artery of the related arch, and 

 not external to that artery, as shown in Parker's figure of Eaja 

 nasuta. In the hyoidean arch, there being no anterior efferent artery, 

 the intermediate commissure is prolonged anteriorly, as in selachians, 

 and meets and fuses with a persisting dorsal portion of the afferent 

 mandibular artery, the commissure thus becoming the basal portion 

 of the definitive afferent pseudobranchial artery. The posterior 



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