( 397 ) 



tendon of the vastus exteruns. The two together form the ligamentum patella, 

 the smallish ossified patella being enclosed in their substance, and are inserted on to 

 the head of the tibia. 



Vastus i/iterni(s.— This muscle arises below the last, but Las not so extensive 

 au origin from the femur ; its short tendon is inserted on to the head of the tibia 

 below and to the inside of the last. 



The Sartorius is a powerful muscle with no peculiarities of origin or insertion. 

 The Ambiens {Pectineus of Owen's description) is well developed, and arises 

 as usual from the pre-pubic pi'ocess; it disappears into the soft tissues of the leg 

 between the two divisions of the rectus femoris, and is inserted, as will be described, 

 into the flexor perforatus. 



The Peroneus longus is a massive muscle covering the front part, and covering 

 the tibialis anticus for nearly the whole of its extent. The tendon, as usual, divides 

 into two — one branch going to the heel, the other becoming continuous with the 

 tendon of the flexor perforans et jiierforatus. 



Peroneus brevis appears to be completely absent. 



Tibialis anticus. — It might be gathered from Sir K. Owen's description of 

 the muscles of this bird that the characteristic long tendinous head arising from 

 the external condyle of the femur was absent. This, however, is not the case. 

 The tendon of insertion is undivided save just at its insertion, where it is perforated 

 by the Extensor dig. III. 



Extensor communis digiforum. — The tendon of this muscle supplies the second, 

 third and fourth toes ; it iirst divides into two branches, and then each of these 

 again divides into two, the middle of the three toes getting two branches. 



The number of the short extensors of the foot has been understated by Owen. 

 There are altogether five of these. 



Extensor digiti HI. — This arises by a long slender tendon from the ligament 

 uniting the tibio tarsus with the tarso metatarsus. It perforates the tendon of 

 insertion of the tibialis anticus, and immediately after swells out into a fleshy belly, 

 which again ends in a long tendon inserted on to the extensor communis tendon 

 just below toes III. and IV. The remaining short extensors, except that of digit I., 

 are covered by a densish fascia, which accounts for their having been missed 

 by Owen. 



Extensor brecis dig. IV. — This, like the remaining extensors, arises from the 

 extensor surface of the metatarsus. Its origin, however, extends further forward 

 than any of the rest. Its tendon, moreover, is attached laterally to the fourth 

 digit, and acts rather as an adductor, as well as to the fourth digit.* The Abductor 

 dig. II. is attached to the inner side of that digit. The Extensores Itallucis and 

 dig. III. are purely extensors in insertion. 



Ga.^trocnemiiis. — This muscle has, as usual, three heads. The outer head 

 springs by a rather narrow head from the femur, which is entirely tendinous. 

 This tendon arises distally to, but nearly in contact with, the long arm of the 

 biceps sling. The short arm of the biceps sling is a broad ligament to which 

 the adjacent flexor muscles are attached on its way to the leg. The inner head 

 of the gastrocnemius is the larger, and arises from the crest of the tibia as well 

 as from adjacent fasciae. The middle femoral head has been already referred to 

 in connection with the accessory semitendinosus. The insertion of the gastrocnemius 

 is in no way peculiar. 



' This luesiimably represents two sliort extensors fused. 



