1894.] MAMMALIAN HAND AND TOOT. 361 



explanation of the two-headed lumbricales of higher mammals, 

 which, e. g. in Man, are so very often met with. 



j3. Extensores. 



Origin. Insertion. 



The supinator longus (bv&chio- Humerus^ Pp., with the tendon of the 



radialis). [as in abd. (ext.) pol. longus. 



The radialis ext. longus. Humerus fnian. Metacarpus II. 



The radialis ext. brevis. Humerus,/ Metacarpus III. 



The extensor dig. comm. rod. Humerus, radius. digits 2-5. 



s. subl. 



The extensor dig. comm. uln. Ulna. digits 1-3. 



s. prof. 



The extensor dig. IV. and V. Ulna. 4th and 5th digits. 



(ext. minimi, Man.) 



The ulnaris externus. Humerus. Metacarpus V. and into 



volar ligaments. 



The prcepotlex gets a very long nerve from the n. medianus, and 

 vessels from the art. brachialis. 



2. Trichosukus ytjlpecuxa. (Plate XXI. fig. 3.) 

 a. Fleccores. 



The ulnaris interims: origin, humerus and ulna; insertion, 

 pisiform. 



The il palmaris longus" consists of two muscles, a superficial 

 and a deeper one ; the superficial one is inserted into the Pp. and 

 the ligam. c. transv., some fibres going to the pisiform : the 

 deeper palmaris ends in the fascia palmaris (vide Plate XXI. fig-3). 



The flexor digitorum sublimis is weak ; it divides into four rather 

 slender tendons which go to digits 2-5, mostly ending in the thin 

 sheaths of the deep tendons. 



The flexor digitorum profundus is strong ; it comes from the 

 humerus and both ulna and radius. The five tendons spring from a 

 united tendinous mass ; they become almost superficial on the 

 digits. 



There oxe four lumbricales. 



/3. Extensores. 



The supinator longus, a strong muscle, arises from the humerus 

 and is inserted on the radial side of the scaphoid (Pp.?). 



The radiales extemi longus and brevis are almost quite separated. 



N. medianus supplies the Pp. ; a strong nerve goes to the dorsum 

 of the hand for the supply of the thumb and the radial side of the 

 2nd digit. 



3. Macbopus bennetti. 



(Zool. Soc. Gardens, London.) 



The palmaris longus ends in a long narrow tendon which 

 continues into a triangular aponeurotic expansion on the wrist, 

 sending a distinct tendinous strip to the Pp., 3rd digit, and Pm., — 

 not only to the bones but also to the pads and even to the skin. 

 Nerve-supply by the ulnaris. 



