FORE-LIMB. 123 



weak. The extensor inetacarpi radialis is so attached to 

 the humerus and base of the thumb that upon extension 

 of the elbow it is tightened, and is capable, without 

 any contraction of its own, of fully extending the hand. 

 0. C. 64 Yp. Presented by St. George Mivart, Esq. 



C. 137. Right shoulder of a Rook ( Trypanocorax frugilegus), 

 showing in more detail than in the previous specimens the 

 levator (supracoracoideus) and rotator muscles of the 

 humerus. A green rod has been placed beneath the supra- 

 coracoideus to show its tendon entering the canal between 

 the bones of the shoulder-girdle. The distal part of its tendon 

 can be seen below the deltoideus minor. 0. C. 64 Y q. 



Presented ly St. George Mivart, Esq. 



C. 138. Right wing of a Wild Duck (Anas boscas) from which 

 the skin of the ventral surface has been removed to show 

 two elastic ligaments. The most important of these 

 (indicated by black paper) is situated along the free border 

 of the propatagium, and represents in a modified form the 

 tendon of the propatagealis muscle. The elastic tissue 

 appears abruptly in the tendon 10 mm. from the muscle, and 

 is attached partly to the distal end of the radius, partly by 

 means of a long inelastic tendon to the base of the thumb. 

 In action it tends to flex the elbow during the recovery, and 

 at the same time tightens the patagium. The other elastic 

 ligament runs along the ulnar margin of the wing and is 

 attached to the quill of each of the remiges; at the elbow it 

 passes into a diffuse layer of subdermal elastic tissue con- 

 nected with the metapatagealis muscle. In this ligament 

 the elastic tissue is mainly present between the feathers, 

 which are by its means drawn together when the arm is 

 flexed. 



Fiirbringer, Anatomic der Vogeln, 1888, p. 583. 



C. 139. Right fore-limb of a Spiny Anteater (Tacliyglossus 

 \_Echidna~\ aculeata), showing the superficial muscles. This 

 limb, both in its musculature and general features, affords an 

 excellent example of the peculiarities associated with digging 

 habits. It is remarkably short and thick-set, and, while all 



