The cephalic vascular anatomy of three species of sea snakes

The primary and secondary elements of the cephalic vascular system in some sea snakes are similar to those of the generalized ophidian pattern. The three species examined in this study revealed only minor variations in vascular morphology; these variations appear to be correlated with myological differences among the three species. For example, in Hydrophis melanocephalus it appears that the depressor mandibulae artery is displaced by the cranially expanded insertion of the semi-spinalis and spinalis muscles. A preliminary hypothesis is put forth that explains the apparent constancy of the cephalic vascular system of ophidians in terms of possible constraints due to cranial kinesis.