554 DR. J. MURIE ON THE ANATOMY OF THE SEA-LION. 
their caudal tendons, the sparse fibres of the intertransversalis mingling with the 
proper aponeurotic fascia of the caudal vertebrae. What may be regarded as the 
infracoccygeus, is therefore but the small inner portion of the sacro-coccygeus, the 
fibres of the former hardly running so high as the latter. It terminates in a strongish 
aponeurotic tendon inserted on the under surfaces of the caudal vertebra, underneath 
the levator ani. 
Levator caude eaternus.—This has an elongated fusiform belly fitting on to the 
outer surface of the levator caude internus, both being firmly encased by a dense 
aponeurosis, and this again overlain by the gluteus medius, maximus, and biceps 
muscles. The former muscle, that in question (L.c.e, figs. 34, 35), arises by aponeu- 
rosis from the superior posterior spinous process of the ilium, and from the outer edge 
and partly superior surface of the transverse processes of the sacrum; thence becoming 
very strongly tendinous, it may be said to be inserted into the first and second caudal 
transverse processes, though still continuing by fascia on the tail. 
This muscle from before backwards lies upon the gluteus minimus, pyriformis, gemelli, 
and obturator internus, and has the long deep sacro-peronus muscle springing from its 
outer side. Its name expresses its function. 
The levator caude internus (L.c.i, L.c.i*) lies wpon the dorsal surfaces of the transverse 
process of the sacrum and caudal vertebrae, between the levator caude externus and the 
prolonged insertion of the erector spine. Its origin, much covered by the erector spine, 
is by a short tendon from the articulating process of the last lumbar vertebra; then, 
becoming fleshy, it is attached to the upper surfaces of the sacral transverse processes. 
At the commencement of the caudal vertebree it becomes highly tendinous, and can 
be resolved into separate tendons, which are inserted, four into the lateral and four into 
the dorsal prominences of the caudal vertebrae. ‘The tendons decrease in thickness 
from before backwards. 
6. Muscles of the Anterior Extremity. (Plates LXX. & LXXII.) 
Pectoral Muscles—The normal division into pectoralis major and pectoralis minor is 
in the Sea-lion somewhat obscure ; for while there are at least three layers of muscular 
fibres in the position of the pectoral muscles, differing entirely in direction, two of 
these may, notwithstanding, only be different portions of the pectoralis major, and not 
the pectoralis minor ; or these muscles are so conjoined in one of the layers as not to be 
separable. The third and smallest division, again, is not the representative of the 
pectoralis minor, but may either be an altered subclayius, or the costo-coracoid of some 
writers. 
The first, anterior and most superficial division (Pl. LX-XIII. fig. 383, P.ma') has its 
fibres pursuing a course nearly transverse to the long axis of the thorax. This broad 
and strong portion has an origin which extends from the manubrium backwards as far 
as the cartilage of the fifth rib.. The muscular layer stretches outwards into the axillary 
