360 Contributions to the 



cle is constantly present, thoui^h varying as to size and 

 insertion in different species ; it does not seem to have 

 been described with much accuracy ; in the lower animals 

 it is often so large as to be called the fourth head of the 

 Triceps; in the Quadruraana it is generally named the 

 " slip from Latissimus dor si to elbow j^ with a conjecture 

 that it may be of some use in climbing ; this it never 

 could be, but the reverse, acting as part of the extensor ; 

 but even if inserted into the olecranon or upon the Tri- 

 ceps, as it sometimes is, it would be of the same use in 

 climbing as the scapular head of that muscle ; but in a 

 large number of cases it is attached to or over the internal 

 condyle of the humerus, thus acting only to draw the arm 

 and body together, without at all interfering with the 

 simultaneous flexion of the forearm at the elbow. Duver- 

 noy describes it in the Gorilla under the name of " Dorso- 

 epitrochlien,^^ and he seems to have understood its true 

 function better than any one else. In the lower Quadru- 

 mana, while on all fours, as in Quadrupeds, this muscle 

 simply helps to retract the fore-leg ; in the cat which climbs, 

 and in the same way as we do, by contracting the whole 

 limb, it is inserted into the internal condyle ; but in the 

 Angora Goat, whose so-called climbing is merely a tall 

 kind of walking, it is almost wholly attached to the long 

 olecranon, tending thus to extend or straighten the whole 

 limb at the same time that it pulls it backward. 



The muscles which flex the arm at the elbow are the 

 same as in man, — Biceps, Brachialis anticus, and Supi- 

 nator longus. The two heads of the first are distinct to 

 within an inch of the insertion, and the coracoid head is 

 the larger. The Brachialis anticus is not easily separable 

 into two parts, or as easily into several. In the Supinator 

 long-US we notice at once a feature which exists also in 

 the flexors of the leg ; its origin is from the two inches 

 below the middle of the humerus, thus as high as the 



