581 



branchial, and quite certainly representing the glossopharyngo- 

 hyoideus section of that artery. A similar artery is shown by 

 Parker in his figure of Eaja nasuta and is there called by him a 

 nutrient artery of the gills, but the artery there has a somewhat 

 different origin, and is shown lying external, instead of internal to the 

 afferent arteries In Eaja erinacea it is not shown by Parker and 

 Davis, and I cannot recognize it in Hyrtl's figure of Raja clavata. 

 Other nutrient branches, the arteriae bronchiales inferiores of Hyrtl's 

 descriptions, arise either from the external lateral hypobranchial or 

 from its commissural connections with the ventral efferent loops, 

 and are sent upward, in each of the four branchial arches, as in Raja 

 clavata, the external lateral hypobranchial then continuing posteri- 

 orly, as the hypobranchial artery, and falling into the subclavian 

 artery. 



Anteriorly, the external lateral hypobranchial is continued for- 

 ward, and passing internal to the common trunk of the hyoidean 

 and first branchial afferent arteries, in the position of an internal 

 lateral hypobranchial, becomes the afferent mandibular artery, as 

 in selachians. This artery first sends branches to the muscles and 

 tissues of the region, and then runs upward between the mandibular 

 and ceratohyal cartilages, and near the dorsal end of the latter carti- 

 lage separates into two parts one of which runs dorsally toward the 

 pseudobranch and the other ventrally toward the mandible. The 

 dorsal branch, as in selachians, does not connect either with the 

 pseudobranch or with the definitive afferent pseudobranchial artery. 

 This afferent mandibular artery is not shown in either Raja nasuta 

 or Raja erinacea. In Raja clavata it is probably the terminal branch 

 of the artery marked c in Hyrtl's figure Taf. 11. 



The coronary artery arises in my specimen, as it does in Raja 

 clavata, from the external lateral hypobranchial between the nutrient 

 branches to the third and fourth arches, and it is connected with 

 its fellow of the opposite side by a cross-commissural vessel that 

 passes ventral to the truncus arteriosus. In both Raja nasuta and 

 Raja erinacea this artery arises from the external lateral hypobran- 

 chial between the nutrient branches to the second and third branchial 

 arches. 



The epibranchial prolongations of the efferent arteries of the 

 first and second branchial arches first unite to form a single vessel, 

 and that vessel, running dorso-postero-mesially, falls into the ex- 



