MYOLOGY OF THE ORNITIIORHYNCHUS. 



153 



Extensor carpi ulnaris. — Of very remarkable size, and bicipital 

 above; whence those who believe in the "serial" homology of the 

 muscles of the limbs might be led to infer that it is the homologue of 

 the gastrocnemius. Its two separate portions above both lie flat and 

 superficial ; the outer determines the contour of the forearm at the 

 part, the inner is appressed in its whole extent against the flexor dig- 

 itorum, from which it is separated by a slight cellular interval. The 

 larger {ulnar) portion arises fleshy from the very edge of the ulna, 

 its upper three-fourths, and still more extensively from the edge, tip, 

 and outer face of the olecranon ; it is flattenecl-ovate in shape, and 

 and has an upper free edge that traverses across the notch between 

 the inner corner of the olecranon and tip of entocondyle, where it is 

 in relation with the " antanconseus." The smaller (liumeral) portion 

 takes origin from the whole length of the base of the entocondyle. 

 These two parts only fuse just before changing into the stout tendon 

 common to both ; the ulnar portion overlaps the condylar. The ten- 

 don is longer than that of the extensor carpi radialis ; it expands as 

 usual to embrace the pisiform bone. The usual action. 



Upon the back of the forearm there are three wrist flexors (i. e., 

 "extensors " of anthropotomy) ; one upon the ulnar side as usual, and 

 only two upon the radial, instead of three (the number when the 

 "supinator longus " is, as it should be, enumerated wtih this set). 

 Of these two radial flexors the humeral origins and general arrange- 

 ment at first favor the supposition that they are the " longior " and 

 "brevior"of anthropotomy, and that there is no supinator longus; 

 but the much more important indication afforded by their insertions 

 below determines pretty conclusively, that one of them is supinator 

 longus, and that either the other represents combined longior and 

 brevior, or that one of these last is missing. 



Supinator longus. — Here seen in its usual character as a humero- 

 carpal, not humero-radial, muscle. Above, it occupies somewhat the 

 position of the flexor carpi radialis brevior, being shorter than, and 

 wholly overlaid by, the other radial flexor. It arises fleshy from the 

 anterior aspect of the external condyle, below the origin of the fol- 

 lowing muscle, lying at first upon the humerus and head of the radius, 

 and then upon the supinator brevis ; finally, upon the back of the 

 radius ; when, becoming tendinous, it passes by the expanded foot of 

 the radius, and is immediately inserted into the carpus, its radial side. 

 It is a pure flexor carpi. 



Flexor carpi radialis (longior or brevior, or more probably both?). — 

 Rather the largest muscle of the parts, and wholly superficial, overly- 

 ing both the supinators; apposed externally against extensor dig- 

 itorum, and on the other side in relation with brachialis anticus and 

 biceps. It arises fleshy from the ectoconclylar ridge, from the tip up- 



