86 THE VOYAGE OF H.M.S. CHALLENGER. 



Action. — The muscle co-operates with the coraco-brachialis in approximating the wing 

 to the side of the body, as well as in rotating that organ inwards at the shoulder joint. 



Relations. — The muscle is concealed superficially by the anterior portion of the 

 latissimus dorsi. Its posterior margin is in contact with the infra-spinatus muscle. 



Nerve sxipply. — A twig from the nerve to the latissimus dorsi, which turns round the 

 axillary margin of the scapula, and enters the outer border of the muscle. 



Remarks. — Cuvier ^ merely mentions the presence in bu'ds of a supra- and infra- 

 spinatus muscle, but does not describe their exact attachments. Gervais and Alix ^ state 

 that in the Penguin {Eudyiites clirysolophus) the supra-spinatus (petit rond) is inserted 

 above the subscapularis. As above stated, I have found that in every species of Penguin, 

 the supra-spinatus and the subscapularis are attached to the humerus by means of a single 

 tendon common to both. 



8. Infraspinatus. 



Sous-scajmlaire, Vicq d'Azyr, 1772, p. 631, N"o. 3. 

 SchuUerblattmiisIiel, Merrem, p. 154:, No. 13. 

 SchuUerhlattmuskel, Wiedemann, p. 87. 

 Supra-.icapularis, Tiedemann, p. 310, No. 8. 

 6'iqjra-scapularis, Heusiuger, p. 184, No. 8. 

 Sous-ipineux, Sleckel, vol. vi. p. 29, No. 5. 

 Infraspinatus v. Teres major, Sclloep^5S, p. 105, No. 13. 

 Infraspinatus, Reid, p. 141. 

 Teres major, Selenka, vol. vi. p. 113, No. 37. 

 Le grand rond, Gervais and Alix, p. 22. 



Attachments. — The infra-spinatus arises from the posterior three-fourths of the dorsal 

 surface of the scapula. The fibres pass forwards and downwards and end on a strong 

 tendon which is inserted into the inner margin of the trici^jital fossa of the humerus one- 

 eiglith of an inch below the bony tubercle which afi'ords attachment to the tendon 

 common to the supra-spinatus, coraco-brachialis, and subscapularis. 



Action. — The. humerus being raised, this muscle is an important, if not the principal 

 agent in bringing about the backward or effective stroke of the wing. This muscle, 

 moreover, rotates the humerus inwards at the shoulder joint, and thus co-operates with the 

 pectoralis major. 



Relations. — Superficially the muscle is covered by the dorsal cutaneous muscle, and 

 hj the anterior portion of the latissimus dorsi. Its upper border lies parallel to, and 

 in contact with the posterior border of the supra-spinatus. The lower border projects 

 considerably beyond the axillary border of the scapula, and forms the posterior boundary 

 of the axilla. 



' Lemons dAnatomie Comparee, toni. i. p. 278. 

 " Loc. cit., p. 22 



