54 
A single extensor (PI. XIII. fig. 1. v), almost equally tendinous and delicate, arises 
from the scapula, and represents the ‘ long extensor’ of Vicq. d’Azyr: it is inserted into 
the rudimental olecranon. 
There is a tendinous trace of a flexor (w) and extensor (x) of the minute monodactyle 
manus: but the motions of the rudimental wing and its terminal hook would seem to 
be produced as much by the cutaneous muscles which converge to be inserted into the 
integument connected with it, as by the feeble representatives of the true wing-muscles 
above described. 
Muscues oF THE Posterior ExtTREMITY. 
The most superficial of the muscles on the outer side of the leg is that very broad 
one which combines the functions of the tensor vagine and rectus femoris, but which, in 
the opinion of both Cuvier* and Meckelt, is the homologue of the tensor vagine and glu- 
teus maximus (seu externus); since however it is exclusively inserted into the leg, I shall 
describe it with the other muscles moving that segment of the posterior extremity. The 
removal of this muscle, of the sartorius, and the biceps cruris, is requisite to bring into 
view the true gluten. 
Gluteus externus (Pl. XI. a).—The external gluteus (gluteus medius of Meckel) is 
smaller, as in most Mammalia, than the middle gluteus, but is relatively larger in the 
Apteryx than in birds of flight, in which it is described as the pyriformis by Cuvierf. 
This muscle, however, besides its origin from the outside of the pelvis, overlaps part of 
the gluteus medius, and has its insertion into the femur at some distance below the great 
trochanter, all of which are marked characteristics of the gluteus magnus. Origin. It 
takes its origin from the superior margin of the os innominatum, extends along an inch 
and a quarter of that margin, directly above the hip-joint, and is chiefly attached by 
distinct short tendinous threads, which run down upon the external surface of the mus- 
cle: it rises also by carneous fibres from the external surface of the os innominatum for 
three lines below the superior margin. Insertion. The fibres converge and pass into a 
tendinous sheet, beginning on the external surface of the muscle half-way down its 
course, which ends in a broad, flat, strong tendon, inserted into a rising on the outer 
side of the femur nearly an inch below the great trochanter. It abducts and raises the 
femur. 
Gluteus medius (Pl. XI. 8).—Origin. This is the large, triangular, strong and thick 
muscle, which has an origin of three inches’ extent from the rounded anterior and superior 
margin of the ilium, and from the contiguous outer surface of the bone for an extent vary- 
ing from an inch to eight lines. Ins. Its fibres converge to a strong, short, broad and flat 
tendon, implanted in the external depression of the great trochanter, having a bursa mu- 
cosa interposed between the tendon and the bony elevation anterior to the depression. 
* Legons d’Anat, Comp, ed. 1836, tom, i. p. 502. + Vergleich. Anat. 1828, Th. iii. p. 361. 
t Loe. cit. p. 508 ; it is here called ‘ pyramidal,’ 
