DR. J. MURIE ON THE ANATOMY OF THE SEA-LION. 575 
which, like the semitendinosus, crosses the abnormally placed groins to the lower leg. 
It arises by a short broad aponeurotic origin from below the transverse processes of 
the first four caudal vertebra; and the muscular expanse, directed transversely and 
slightly backwards, is attached by membrane to the inner edge of the tibia from its 
middle (posterior to the semitendinosus) to the malleolus, where its tendon mingles with 
that of the gracilis, the two proceeding to the sole of the foot. This muscle is somewhat 
narrowed at its middle, and is much broader at its insertion than at its origin. 
Relations &c. ‘The sacro- and ilio-coccygeus lie beneath it, at the tail; and con- 
tinued behind is the (transverse) levator ani. It partly hides the lymphatic gland and 
the deep ischiatic vessels, &c. It crosses the gastrocnemius and long flexors of the foot 
above the ankle, and itself is covered by the gracilis. The broad biceps, and additional 
belly of the same, are situated behind or dorsally. Adductor and rotator inwards of the 
lower leg; or, when the leg is fixed, it drags the tail to the side. 
Additional attitudes at times assumed by the Sea-lion. From life. 
There is only a single broad inner head to the gastrocnemius muscle (figs. 34, 36, & 
37, Ga). Its attachment is the inner condyle of the femur, its lower border, by a broad 
flat semitendinous origin, also the inner side of the head of the tibia and over the internal 
lateral ligament of the knee-joint. The muscular belly is broad, and only moderately 
thick, and, as it pursues its course downwards, lies obliquely upon the inside of the 
leg, instead of posteriorly, as is usual when it is double-headed. It is fleshy to within a 
couple of inches from the heel, and ends in a strong flattish tendon inserted inte the 
os calcis, running partly over it, and apparently continuing or giving rise to the extensor 
brevis digitorum. 
VOL. VU.—PaRT vil. January, 1872. 4N 
