130 Prof. A. Macalister on the Muscular Anatomy 



capsule ; pecforalis quartus^ froin the cartilages of the lowest 

 four ribs to the shoulder-capsule ; and a thu'd pectoral [pecto- 

 ralis minimus of Wenzel Grube), from the manubrium sterni 

 and cartilage of the first rib to the shoulder-capsule. The 

 suhclaviusj under a strong costo-coracoid membrane, stretches 

 to the posterior margin of the outer third of the clavicle. 



The deltoid is a single muscle, composed of its three parts 

 united inseparably, and sending an extensive offshoot at its 

 insertion, which is continuous into the origin of the sujjinator 

 longus. The capsular muscles are developed in the following 

 proportions : — deltoid=^ 1 , sujjrasjnnatus = 1*11, infraspin atus 

 = 1'69, teres minor (exceedingly thin, with a marginal tendi- 

 nous origin for one fifth the axillary costa of the scapula 

 and an unusually wide fleshy insertion) =*08, suhscapularis 

 = 2, teres major =1. 



The hiceps is, as usual in Marsupials, composed of a partially 

 united gleno-idnar and a coraco-radial muscle ; the latter re- 

 ceives a large fascicle from the former ; the hrachialis anticus 

 is long ; the triceps externus and internus are united ; and the 

 muscles of this region have to each other the following propor- 

 tions : — hiceps coracoidalis =1^ gleiioidalis = 0'G8y hrachialis 

 = 0*8, tricejys longus = 2, tricep)s externus and inter7ius = 2'6, 

 dorsi epitrochlearis (which is inserted into the inner condyle and 

 olecranon) = 0"-i4. There aretwoa;?conffi/, external and internal. 



'^^ho, pronator and supinator muscles are well-developed. The 

 round pronator has but one head ; and the quadrate pronator 

 occupies the lower sixth of the forearm. Supinator longus, 

 besides an origin from the deltoid, is attached to the lower half 

 of the humerus ; Mid its tendon, passing under the tendon of the 

 abductor major p)ollicis and lying on the wrist synovial mem- 

 brane, was inserted into the scaphoid bone. The supinator 

 hrevis occupies two fifths of the radius. These muscles are 

 developed in the following proportions : — Pronatores : supina- 

 tores :: 1 : 4. 



The other muscles in the forearm are well marked. The 

 radial and ulnar flexors of the carpus and the palmaris longus 

 are simple and normal ; the flexor suhlimis digitorum arises 

 from the front of the deep flexor, and is exceedingly feeble ; its 

 tendon for the fourth finger is the strongest. The deep flexor 

 consists of four heads — one condyloid, one olecranal, one 

 radial, and one ulnar ; five tendons spring from this ; but the 

 polliceal tendon is not from the radial border of the common 

 tendon, but springs from the front of the tendon inside the edge, 

 as is sometimes the case in the Quadrumana. 



The extensores carpi radiales are as usual, and are inserted, 

 not into the carpal ends, but into the middle of the shaft of 



