MACROSCOPIC OBSERVATIONS OF THE FACIAL-MUSCLES IN THE BAIKAL SEAL (PHOCA-SIBIRICA)

This study was performed to determine if, as expected, the enlarged ey e of the Baikal seal (Phoca sibirica) has an influence on the form and function of the skull and facial muscles. Macroscopic observation of these muscles demonstrated that the M. orbicularis oculi expands aroun d the palpebral fissure and that some facial muscles attach and insert in the M, orbicularis oculi, possibly supporting M. orbicularis oculi function. We suggest that these muscles move the eye and palpebral ar ea and constitute a morphological and synergistic facial muscle comple x system. Further, the development of the M. rectus lateralis around t he sclera of the eye indicates that this muscle is also involved in ey e movement.