DR. J. MURIE ON THE ANATOMY OF THE SEA-LION. 045 
it again is itself overlapped at its front border by a portion of the immense cephalo- 
humeral muscle. The second trapezial segment, at its scapular attachment, has its 
fibres running on and interweaving with those of a portion of the deltoid. 
The rhomboideus capitis (fig. 20, Rh.c)is a very large, expanded muscle in the Sea-lion. 
Its fibres reach well up towards the occiput in the nuchal region ; and its posterior fibres 
extend behind to as far as the fourth dorsal spine. It is attached in the median line to 
its fellow of the opposite side. Those muscular fibres posteriorly placed are directed 
partly outwards, downwards, and backwards, following in this way the curves of the 
back and shoulder; they are inserted into the posterior half of the vertebral edge of 
the scapula, and into the scapular spine for half its length. A small portion of the 
posterior angle of this muscle is covered by a fold of the serratus magnus. 
The rhomboideus major and minor in this species of Otaria are represented by a 
single muscle; and this, from the attachments, is more likely to be the rhomboideus 
minor. It is a broadish thin slip of muscle (see fig. 20, Rh.m/) arising fleshy from 
the fourth, fifth, and sixth dorsal spines. Its insertion is into the deep side of the 
superficial part of the fold of the serratus magnus, 1} inch behind the scapula, but 
having no insertion into the latter bone itself. 
The spinalis dorsi (fig. 21, Sp.d), emerging from the composite erector spin in the 
lumbar region, goes on as far as the first dorsal spine and then tapers to a point. This 
muscle is almost equal in bulk to the other long dorsal muscles. 
Two other sets of vertebral muscles may be here mentioned, the semispinalis ($Sp) 
and rotatores (Ro, fig. 22). Both are fully developed, and strong in their individual 
component parts in the dorsal region. They are each composed of broad fieshy fasci- 
olar bundles; the former start from the roots of the transverse processes, and lie 
athwart the spines; the latter proceed from the tips of the transverse processes, and 
pass forwards to the lamina of the vertebra in advance. 
The sacro-lumbalis muscle (S./), as might be expected, is of considerable size, and in 
this case equals the longissimus dorsi. It has the usual origin from the lumbar region, 
and as it proceeds forwards it sends superficially outwards very broad, flat, strong 
tendons to all but the last two ribs, while deeper and on its inner side small delicate 
tendons are sent to all but the two anterior ribs, or rather to the articulating processes. 
The longissimus dorsi (Lo.d), after its continuation forwards from the common mass of 
the erector spine, sends out tendons in a similar manner as the sacro-lumbalis, which 
are inserted into the eight anterior dorsal apophyses. There are, moreover, fleshy slips 
and tendons combined, which proceed to the metapophyses of the sixth, fifth, fourth, and 
third cervical vertebre. This portion it is which represents the transversalis cervicis 
muscle (7c). 
Splenius capitis and colli.—These muscles reverse the condition which obtains in Man, 
inasmuch as they are single in insertion and double in origin. The former (fig. 21, Sp.c) 
arises narrowly by muscular fibre in the region of the shoulder and the neck, from oppo- 
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