274 ZAGLOSSUS. 



for the Echidna, arismg by tendinous fibers from the median edge of the uhia 

 just distal to the sigmoid notch and by fibers from the ligament between ulna 

 and radius. Proximally the muscle is closely applied to the supinator, and then 

 passes as a stout flattened tendon across the tendons of the extensores carpi 

 radialis longus et brevis to insert on the radial side of the first metacarpal. 



The pronator teres (Plate 1, fig. 2, pt; fig. 3, pt) is strongly developed. 

 It has origin by a flat tendon from the medial edge of the internal epicondylus 

 of the humerus and is partly covered by the flexor carpi radialis. The muscle 

 thickens in the middle, and becomes somewhat triangular in section. Distally 

 it flattens again and inserts by muscular fibers along the medial edge -of the 

 radius from the insertion of the biceps to the epiphysis. 



The flexor carpi radialis (Plate 1, fig. 3, fr) is a large, radially compressed 

 muscle, arising from the anterior edge of the internal epicondylus of the humerus 

 slightly external to the origin of the pronator teres, whose base it slightly over- 

 laps. It passes into a stout tendon at the beginning of the terminal third of the 

 fore arm and inserts into the proximal end of the second metacarpal, ventrally, 

 and by a continuation of the tendinous portion it is likewise united with the 

 first metacarpal. The condition is essentially the same as in the Echidna. 



The palmaris longus is lacking, at least as a separate muscle. Mivart 

 considers that it is fused in the Echidna with the flexor profundus digitorum.. 



The flexor carpi ulnaris (Plate 1, fig. 3, fa) is from two heads as usual: — 

 (1) for nearly one third the length of the ulna from the olecranon along its 

 ectal edge, (2) by a smaller flatter muscle arising at the ectal corner of the 

 epicondyle of the humerus, where it partly overlies the most exterior head of 

 the profundus. Tlie ulnar head is the larger and the tendons of the two unite 

 just proxuTial to the distal head of the ulna and insert as usual into the pisiform 

 bone. Proximally the second head is united by a few fleshy fibers to the base 

 of the profundus. 



The flexor sublimis digitorum is lacking as a separate muscle. 



The flexor profundus digitorum (Plate 1, fig. 1, /;; fig. 3, p) is enormously 

 developed and arises from four heads: — (1) an ulnar head, from the proximal 

 two thirds of the inferior surface of the ulna and from fascia between the radius 

 and ulna; (2) from the angle of the internal epicondylus of the humerus where 

 it is partly covered by the second head oi flexor carpi ulnaris; (3) a thick portion 

 arising also from the internal epicondylus, just medial to the second portion 

 of the profundus, to which it is intimately connected by muscular and tendinous 

 fibers; (4) a deep lying slender and spmdle-shaped muscle quite distinct from 



