THE MUSCLES OF THE LOWER EXTREMITY. 



167 



names of gluUeus quartus and glutceus quintus, in the 

 Cassowary ; one of them is absent in most birds " [Anat. 

 of Verts., vol. ii. pp. 100-101). 



The two smaller gluteals pull the thigh-bone forwards 

 while at the same time they abduct it. 



The group of gluteal muscles are also powerfully de- 

 veloped in our Geococcyx califoiiiianus. In it " the 



^^•^Z 



Fig. 45.— Aiiterioi' aspect of left femur of a Raven, designed to show the muscles 



that are attached to it. 

 Fig. 46. — The same hone seen from behind ; a, femoral head of the flexor 



ppA'forans digitonmi 2)rofundus. 

 Fig. 47. — The same bone viewed from its inner side. All life-size, by the author, 



from his own dissections. 



gluteus primus (Fig. 62 his) constitutes that great and 

 rather complex muscle which makes up the central fleshy 

 portion of the outer aspect of the thigh. It arises by a 

 strong fascia from the summit of the co- ossified neural 

 spines of the anterior sacral vertebrae, and by carneous 

 fibres from the outer rim and under surface of the 



