DR. J. MURIE ON THE ANATOMY OF THE SEA-LION, 547 
usual, between the axis and the atlas, coming from the spine of the former and inserted 
into the entire length of the transverse process of the atlas. 
Besides the foregoing set of deep muscles, there is another which ought to come 
under the description of this group. In size and direction it is nearly equal to, and runs 
parallel with the obliquus inferior (vide fig. 25,*). It arises from the articulating pro- 
cesses of the second and third cervical vertebrae, and, proceeding forwards and outwards, 
is inserted into the posterior surface of the tip of the transverse process of the atlas. 
The intertransversalis and the interspinalis (Isp) muscles are each remarkably well 
developed. They are especially very fleshy and large in the posterior cervical and 
dorsal regions. 
Although there is great mobility and power of neck in Otaria, there is no ligamentum 
nuche present. 
Levatores costarum.—These in Otaria are fifteen in number, and thus correspond 
with the number of the ribs present. ‘They have attachments similar to what is found 
in the human being—namely, from the transverse processes of the dorsal vertebrae to the 
ribs. As in Man, also, the first of these muscles comes from the last cervical vertebra 
(fig. 22, L.ct). The hindermost do not, however, present insertions into two ribs, as is 
often the casein Man. Each muscle, or muscular slip, considering the whole as one 
series, is narrow and superficially tendinous at its origin, widening gradually and 
becoming fleshy as it proceeds backwards and downwards to be inserted broadly into 
the anterior marginal costa. Those in the dorsal region are remarkably large and 
muscular. The action of the levators of the ribs in the Sea-lion is somewhat of a limited 
rotary one. Lyery individual slip is of a nearly equal-sided triangular form; and the 
plane or direction of force is from the anterior angle to the base or posterior side of 
the triangle. During contraction therefore the fibres, while drawing the rib directly 
forwards, also tilt its anterior edge outwards and forwards. 
Cephalo-humeral.—This muscle, usually well developed in the Carnivora, is in the 
Sea-lion of most remarkable size, and, as might be expected from its attachments, 
powerfully affects the movements of the fore limb. Its most anterior point of origin is 
from the occiput; and from this the fibres extend backwards along the spinal line of 
the neck to opposite the vertebral border of the scapula, where the posterior fibres 
slightly overlap those of the anterior border of the second portion of the trapezius. 
The muscular fibres of the cephalo-humeral are remarkably strong, and coarse in 
texture. They continue from the above extensive origin as a broad sheet, and cover 
almost the entire side of the neck and the front of the shoulder (fig. 15, Ch). The 
fibres more or less converge as they proceed downwards and backwards; and winding 
round the front of the shoulder, part of them are inserted into the musculo-cellular 
tissue, representing the absent clavicle; the remainder, the wider and stronger portion, 
go down to the deltoid ridge, and are even continued on to the superior portion of the 
second head of the brachialis anticus. (Vide insertion, C.h, fig. 27.) 
