T. Jeffery Parker, op. cit. p. 691.
Cf. Figs. 195 and 196.
Ramsay Wright, Journ. Anat. and Phys. xix. 1885, p. 482; F. W. Müller, op. cit.
These vessels are not to be regarded as homologous with the primitive paired aortae of Amphioxus and the embryos of higher Vertebrates. The true dorsal aorta sometimes persists as a median vestigial vessel which traverses the circulus cephalicus.
For the relations of the efferent branchial vessels to the cephalic circle and the median dorsal aorta in different Teleosts, see Ridewood, P.Z.S. 1899, p. 939.