104 ANATOMY OF VERTEBRATES. 



knee-joint, sends off at right angles a broad and square sheet of 

 aponeurosis, which glides between the tAVO origins of the gastro- 

 cnemius interims, and is inserted into the lower part of the angular 

 ridge continued from the inside of the head of the tibia. The 

 terminal tendon, continued from the apex of the muscle, then 

 runs along the outer or fibular margin of the internal head of the 

 gastrocnemius, and becomes confluent with the tendon of that 

 muscle. 



The crurccus ^ is a simple but strong muscle : it commences at 

 the upper and anterior part of the thigh by two extremities, of 

 which the outer and upper one, representing the vastus externus, 

 has its origin extended to the base of the trochanter ; the inner 

 and inferior comes off from the inner side of the femur, beneath 

 the insertion of the glutceus magnus ; the two portions blend into 

 one muscle much earlier than in the Ostrich. It is inserted by 

 the ligamentum patellie into the fore-j^art of the head of the 

 tibia. 



The gracilis- lies on the inner side of the crurceus, but more 

 superficially ; it rises by two heads, one from the anterior and 

 upper part of the femur, the other from the os pubis ; both soon 

 become blended together and transmit a broad thin tendon to be 

 inserted into the lower and lateral part of the patella with the 

 crurcEus. 



Two other muscles succeed the j)receding, and rise beneath it 

 from the inner and anterior part of the femur ; they have a 

 similar insertion, and obviously represent the vastus internus^^ 

 The fibres converge to a middle aponeurosis, which increases to a 

 strong short tendon, inserted into the uj)per and anterior projec- 

 tion of the tibia. 



Popliteus. This small muscle is brought into view when the 

 superficial muscles of the leg which are inserted into the foot are 

 removed. Its carneous fibres extend from the fibula inward and 

 downward to the tibia. It is of relatively smaller extent than in 

 the Cassowary. 



Gastrocnemius. This complex and powerful muscle consists, 

 as in other Birds, of several distinct portions, the chief of which 

 correspond with the external and internal origins of the same 

 muscle in Mammals. The gastrocnemius externus'^ arises by a 

 strong, narrow, rather flattened tendon from the ridge above the 

 external condyle of the femur, which, about an inch below its 



' XI-. vol. iii. pis. 32, 35, o. - lb, pi. 35, P. ^ lb. pi. 35, Q. 



^ lb. pis. 31, 32, R. 



