580 DR. J. MURIE ON THE ANATOMY OF THE SEA-LION. 
the tendon of the gastrocnemius. Its thick fusiform belly fills the interval between the 
os calcis and the fifth metacarpal, ending, however, in a double belly and insertion. 
One of these, the shortest and thickest, ends in the proximal end of the fifth metacarpal 
bone; the outer and longer belly continues to the distal end of the same metacarpal, 
and to the proximal extremity of the first phalanx of the fifth digit, being inserted there 
by tendon along with the flexor brevis digitorum. Between the two bellies and points 
of insertion of the abductor minimi digiti the flexor brevis digitorum lies. 
The shortest of these muscles or bellies may represent Huxley's abductor ossis 
metacarpt quinti (Ab.o.m.5) % 
TY. Ligamenrous System. 
1. Spino-cranial Connexions. 
The articulations of the head and trunk manifest considerable likeness to those of 
other Carnivores, their chief difference being laxity and fulness. This, of course, 
admits of great mobility of the parts; and hence in those wonderful movements and 
attitudes the bones glide one on the other in a manner not even equalled in the mani- 
fold contortions of the human acrobat. The peculiar softness and thickness of the 
intervertebral cartilages moreover conduce to spinal flexions of an unrivalled character, 
so varied and so graceful are they. ‘The head sits upon the atlas very loosely indeed; 
and therefore twisting of the head in almost every direction occurs with ease. In the 
diagram (fig. 42, Pl. LX XIII.) I have shown in profile the posterior occipito-atlantal 
ligament (p.0.a@), which has a moderate development in thickness. It and the anterior 
occipito-atlantal ligament are considerably strengthened, however, by a triangular, 
oblique, and strong accessory band (ac), which stretches from the vertebral lamina to 
the basioccipital bone. 
2. Articulations of the Fore Limb. (Plate LXXII.) 
Shoulder-joint.—The capsular ligament of the shoulder-joint is of moderate strength, 
and has the usual mammalian attachments—namely, between the scapula and humerus. 
The coraco-humeral ligament is barely distinguishable from the capsular, excepting in 
a slight increase of thickness in the ligamentous substance of that part. 
Scapular Ligaments.—The ordinary coraco-acromial ligament of the scapula is absent. 
The acromio-glenoid ligament is short and narrow but strong. It passes between the 
diminutive coracoid process and the outer side and middle of the neck of the scapula. 
It forms a small foramen. 
Elvowjoint.—The flattening which the limb undergoes, the radius being placed com- 
pletely in advance of the ulna, does not in the main greatly affect the distribution, 
number, or position of the cubital ligaments and those of the wrist-joint, as might at 
first be supposed from the altered relation of the parts. The change of position, how- 
ever, has a marked influence on the movements of the bones the one upon the other. 
