102 



BULLETIN OF THE IU'REAT <>F FISHERIES. 



ventral median hypobranchial artery, fourth, fifth, and sixth commissural arteries, 

 and indications of a lateral hvpobranchial artery. 



In individuals of the same species, as well as in species, teleosts show much 

 variation as to the arrangement of their hvpobranchial and commissural vessels, all 

 tending to indicate a primitive condition, such as is found in the Elasmobranchii, 

 where the ventral ends of all the efferent branchial arteries of each side are connected 

 by means of a lateral longitudinal vessel — the lateral hypobranchial artery of Parker 



& Davis — and where vessels (commissural 

 arteries) from these lateral hypobranchial 

 arteries run toward the median line and 

 unite to form the median hvpobranchial 

 artery. As Parker & Davis have pointed 

 out. the usual arrangement of these vessels 

 in teleosts is a single pair, the fourth com- 

 missural arteries running toward the median 

 line, where they join to form the median hy- 

 pobranchial artery. Parker (1899 and 1900), 

 however, describes for Mola the presence of 

 dorsal as well as ventral coronary arteries, 

 and considers more than one pair of commis- 

 sural arteries a remarkable condition not 

 likely to be possessed by a teleost. The 

 writer has found lateral hypobranchial ar- 

 teries, as well as dorsal coronary arteries, 

 in a number of teleosts in addition -to Mola. 

 In a kingfish (Menticirrh us) the ventral ends 

 of the first, second, and third efferent bran- 

 chial arteries were connected by a lateral 

 hvpobranchial, while in a tomcoi~(Microga- 

 dm, tig. 13) the ventral ends of all four of 

 the efferent braneial arteries were connected. 

 The third, fourth, and fifth pairs of com- 

 missural arteries were also present in this 

 individual. 



Th, fourth efferent branchial artery (fig. 

 U>, pi. i, and fig. 12). This artery, which as 

 a rule has no branches, joins the third efferent 

 branchial artery to form the second root of the dorsal aorta. A small artery (53) 

 arises from the ventral surface of the second aortic root, and. running ventrad and 

 lateral!, ' divides into branches which supply the sides of the pharynx, superior 

 pharyngeal teeth, and membranes on the rudimentary fifth branchial arch. 



Fig. 13. — Ventral ends of the efferent branchial vessel: 

 and their branches in the touieod. Ventral :i*p. ri 

 I 





THE DORSAL AORTA AND ITS BRANCHES. 



The dorsal aorta (fig. Hi, pi. I, and fig. 15) is formed by the junction of the two 

 pairs of aortic roots, and extends caudad along the ventral surface of the vertebral 

 column in a series of undulations which correspond to the topography of the ventral 



