ART. 15 ANATOMY OF THE EARED AND EARLESS SEALS HOWELL 53 



same course. This name now seems to me unfortunate, as the levator 

 angulae scapulae is often so called and the two are entirely distinct. 

 It therefore is preferable to refer to it according to its function which 

 is a depressor of the scapula. In various animals this part of the 

 L^heet is variable, and purely for convenience it will be divided into a 

 cervical and a thoracic part. 



M. depressor scapulae (figs. 7, 18, 19) (levator scapulae part). In 

 the Zalophus the cervical part arose by digitations from the anap- 

 ophyses of the last five cervical vertebrae, directly adjoining the 

 atlantoscapularis superior. It was continuous with the costal part, 

 arising not by distinct slips but practically continuously from the 

 fascia over the angles of the first four ribs. This part passed deep 

 to the costal portion of the scalenus and together with pars cervicis 

 the whole sheet was inserted along the entire vertebral border of the 

 scapula save for about 25 mm. of its most cranial part. The caudal 

 25 mm. joined the broad tendon of the serratus magnus. In the 

 Phoca origin of the cervical portion was the same and of the costal 

 portion, from the ventral terminations of the bony parts of the first 

 two ribs. Insertion was upon the medial aspect of the vertebral 

 border of the scapula from opposite the spine caudo-ventrad around 

 the glenovertebral cartilage. In Eumetopias insertion of this, as a 

 part of the serratus magnus, included the atlas, this possibly being my 

 atlantoscapularis superior. 



M. serratus magnus (figs. 7, 16, 17, 18, 19) in the Zalophus was 

 exceedingly powerful and was placed to best advantage for a back- 

 ward pull of the scapula. Origin was by fascia from as far craniad 

 as the second rib, thus overlying the depressor scapulae costalis for 

 the distance of two intercostal spaces. Origin continued fascial to 

 the fourth rib and thence to the tenth it was from the bony termina- 

 tion of each rib and the caudal border of its cartilage. The more 

 ventral portion of the muscle was partly aponeurotic but it rapidly 

 increased in thickness until near insertion it was some 10 mm. deep. 

 The more dorsal fibers had an inclination directly craniad to the 

 insertion, 25 mm. in length, upon the glenovertebral angle of the 

 scapula. The anterior half of this was broadly tendinous, and being 

 laterad of a part of the depressor scapulae, fibers of the latter also 

 joined it. In the Phoca origin was from as far caudad as the 

 twelfth rib. The digitation from the fifth passed over, and from 

 the third and fourth under, the scalenus. It is doubtful if origin 

 should be considered as reaching farther craniad than the third rib, 

 as anterior to that the muscle sheet was of a much finer texture, but 

 there was no discernible division between this muscle and the de- 

 pressor scapulae. Insertion was as in Zalophus. Miller stated that 

 in P. vitulina origin was from as far caudad as the tenth and in 



