DE. J. MTJEIE ON THE FORM AJSTD STETJCTTJEE OF THE MANATEE. 157 



Manatee. This has a fleshy origin from the entire length of the prominent ridge of 

 the outer occipital, thence is directed nearly vertically outwards and backwards, 

 marked by limiting the anterior flattened surface of the shoulder. It continues 

 obliquely round the head of the humerus immediately in front of the deltoid, at 

 this part resembling the latter in shape, and is inserted on the inner and anterior 

 side of the neck of the humerus by a very short, but strong, tendon. The humeral 

 attachment is on a level with that of the deltoid, above that of the pectoralis major, 

 and close to the front upper edge of the biceps. 



Although a clavicle is absent, a muscle corresponding to a levator claviculse (l) exists. 

 It is a narrow fleshy slip arising from the paramastoid directly behind the stylo-hyal 

 and origin of the digastric. Coursing downwards and backwards parallel with the 

 anterior border of the cephalo-humeral, it becomes fused with this last at the head of 

 the humerus. There is a slight transverse fibrous line of demarcation where the levator 

 terminates ; and this, it may be, is a repi-esentative of an osseous clavicle. At the head 

 the muscle is in close relation with the hinder part of the parotid gland ; and a small 

 portion of the glandular substance and several vessels separate it from the cephalo- 

 humeral. 



The two above muscles apparently have a combined action, and drag the pectoral 

 extremity forwards, upwards, and fully rotate it outwards. They doubtless oppose the 

 latissimus dorsi and teres major; but the shortness of their leverage must detract from 

 any great power. 



The pectoralis minor agrees with the pectoralis major in being relatively long and 

 narrow. It springs from the anterior portion of the rectus abdominis over the fibrous 

 cords or sternal cartilages of the second and third ribs, and from the projecting sharp 

 angle of the sternum, not reaching, however, the median line. As the muscle trends 

 forwards it narrows slightly, and finally is inserted into the head of the humerus. 



Several large glands lie beneath the muscle ; and axillary vessels and nerves pass 

 beneath it, the rete mirabile being closest to its deep surface. 



The pectoralis major muscle is thick and powerful, though relatively narrow. It has 

 origin from the whole length of the sternum, and from the median line of the abdomen 

 two inches beyond the ensiform cartilage, where it overlaps a small inner portion of 

 the anterior inner edge of the rectus. The muscular fibres take a direction obliquely 

 or sharply forwards and outwards, and are inserted, by a very strong short tendon, 

 into the upper portion of the lower third of the thoracic aspect of the shaft of the 

 humerus. There is only an indistinct division into sternal and manubrial portions, 

 which might be overlooked, except that the former rolls somewhat round, or rather 

 dips beneath, the anterior more fleshy moiety at the axilla. 



The humeral tendon of the pectoralis major while firmly implanted into the deep pit 

 or continuation of the bicipital groove on the inner and lower aspect of the shaft of the 

 bone, also possesses continuity with the radial segment of the forearm. Adduction of 



