62 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 7:j 



humeral and inserted along the dorsal three-fifths of the spine of 

 the scapula. In Arctocejihahts this was called rhomboideus capitis 

 by Miller and was similar to my Zalophus. According to Murie 

 conditions were quite different in Eumetopias. He termed it rhom- 

 boideus capitis, with origin from the middorsum of the cervical and 

 anterior thoracic region and insertion upon the dorsal part of the 

 spine and the caudal half of the vertebral border of the scapula. In 

 Odohenus it did not extend caudad of the spine along the vertebral 

 border. In my Phoca origin was from tho. nuchal ligament as far 

 craniad as the occiput. It passed deep to the vertebral border of the 

 scapula and inserted along the caudal border of the glenovertebral 

 cartilage, its fibers fasciculating with those of the serratus magnus. 

 For his Phoca Miller described tw^o anterior rhomboids — a capitis 

 and a cervicis — ^but from his text I can not tell whether these were 

 entirely separate muscles (one corresponding to an occipitoscapu- 

 laris) or two divisions of what might be considered as a single sheet. 

 Attachment to the whole vertebral angle of the scapula is indicated, 

 but otherwise conditions were similar to my Phoca. 



M. rhomboideus dorsi (figs. 7, IT) in the Zalophus arose from mid- 

 dorsad by interdigitations of its fibers with those of its antimere. 

 It was a rather decadent muscle, and its coarse, loosely connected 

 fibers ran laterad to insert upon the vertebral border of the scapula, 

 from slightl}'^ craniad of the spine to the glenovertebral angle. Murie 

 considered that this represents the major and minor divisions. In 

 the Phoca it was similar, save that insertion was only by fasciculi 

 into a part of the insertion of the serratus magnus along the ventral 

 border of the glenovertebral cartilage. 



M. atlantoscapularis superior (figs. 7, 16, 17, 19) in the Zalophus had 

 origin from the transverse proceess of the atlas just entad of the in- 

 ferior division of this muscle. It was slender and extended to 

 aponeurotic insertion upon the vertebral border of the scapula for a 

 short distance just craniad of the spine. Near the insertional end it 

 was parallel to the fibers of the depressor scapulae and one can 

 readily see that the two muscles might fuse, the sheet then being 

 folded over the coracovertebral, angle. Authors have expressed 

 doubt, from time to time, that either division of this muscle as here 

 termed is homologous wdth the human levator (anguli) scapulae. 

 The innervation in a large number of diverse mammals will have to 

 be investigated before this point is settled, but at any rate it would 

 be theoretically easy for this superior slip to migrate ventrad along 

 the anterior border of the scapula, or for the inferior slip to migrate 

 en to the head of the humerus, as is actually the condition in Phoca, 

 and then dorsad to the more usual levator anguli scapulae position. 

 Conditions were the same in my Phoca save that insertion was dor- 



