202 THE MYOLOGY OF THE RAVEN. 



leg, and merge into the l)rocid tendinous expansion 

 already alluded to in tlie last paragraph. The free edges 

 of this portion are firmly attached by strong fasciae 

 to the mesial margins of the other two divisions. The 

 tendon of the biceps passes between this head and the 

 external one, while the fascia of the accessory scmitcn- 

 dlnosus is attached to its outer free edge above. 



The tibial head of the gastrocnemius has a l)road 

 and fleshy origin from the entire inner rim bounding 

 the tibial summit and from the free edge of the adjacent 

 procnemial crest (Fig. 50). 



This division of the muscle is somewhat laro;er than 

 the external one, though of a very similar form, its 

 fibres below converge into a point which is situated 

 rather lower down than the distal terminations of the 

 carneous portions of either of the other divisions, and 

 this point merges into the narrower portion of the 

 common tendon of the muscle. This tendon, the super- 

 ficial and median one of the lower fourth of the leg, 

 develops in it, between the distal tibial condyles, a 

 semilunar flattened piece of cartilage, which rides in 

 a longitudinal groove over the true tibial cartilage, 

 and is braced into position by a firm fascia, at the 

 back part of the tarsal joint. Below this, the tendon 

 of the gastrocnemius, hardly reduced in size, though 

 gradually becoming thinner, passes down directly 

 over the other tendons at the back of the tarso- 

 metatarsus, to merge into the fascia over them at 

 about the middle of the l)one. In all the lower part 

 of its course it is held in its position by a strong 

 fibro-tendinous fascia, fully capable of resisting the 

 most powerful contractions of the muscle. 



By way of comparison with what we have just 

 given above for the Raven, we find this muscle wonder- 



