678 DR. p. CHALMERS MITCHELL ON THE 



bellies remaining separate until their insertion, so that the muscle 

 is completely double. In Lejytoptilus the tendons fuse distally. 



Extensor vietacarpi ulnaris. — Arises from the external condyle 

 of the humerus by a tendon superficial to that of the ectepi- 

 condylo-ulnaris ; then a long fleshy belly, then a thin tendon 

 passing over a groove in the distal end of the ulna from which it 

 receives a strong anchoring slip, absent in Lejjtojitilus, to its in- 

 sertion on metacarpal II just where metacarpal III is given off'. 

 ■ Flexor dlgitorum suUimis. — A strong band of tendon runs 

 from the inner condyle of the humerus to the ulnar carpal, from 

 the upper side of which the flexor digitorum sublimis arises as a 

 delicate fleshy muscle giving rise to a slender tendon which passes 

 over a groove in the ulnar carpal and is inserted to the base of 

 phalanx 2 of digit II, but with first an insertion to the base of 

 the first phalanx of that digit, which I do not find recorded in 

 ni}" notes on Leptoj^tiliis. 



Flexor digitorum profundus. — Arises fleshy from the second 

 and third fifths of the ulna, very closely connected with the in- 

 sertion of the ectepicondylo-ulnaris. The tendon begins where 

 the origin from the ulna ceases, and runs down the radial face of 

 the ulnar carpal under the ligament from the radius to meta- 

 carpal II, and then follows the tendon of the superficial flexor to 

 be inserted just beyond it to phalanx 2 of digit II. It receives 

 n strong slip from the short extensor of the thumb, which I did 

 not record in the case of Leptoptilus. Gadow mentions somewhat 

 similar relations with the thumb in the. case of Owls and 

 Heliornis. 



Extensor digitoriom communis. — Arises tendinous from the 

 external condyle of the humerus and passes into a slender belly a 

 quarter way down the forearm, but receives no fibres from the 

 ulna. Its tendon of insertion passes through a groove in the end 

 of the ulna and then sends a branch to the base of phalanx 1 of 

 dip-it I and a stronger tendon to phalanx 2 of digit II. As in 

 Eepto23tilus. 



Extensor pollicis longus. — Two slender fleshy heads from the 

 adjacent surfaces of the radius and ulna at their proximal ends, 

 with accessory fibres from a large part of the length of the radius 

 on its ulnar face. Tendon unites with that of the extensor 

 metacarpi I'adialis at its insertion. As in Lpptoptilus. 



Extensor indicis longus. — One head fleshy from the distal half 

 of the radius and a second much smaller, tendinous from the 

 distal end of the radius and from radial carpal. Insertion to the 

 second phalanx of digit II, but attached by fascia to the first 

 phalanx. As in Leptoptilus. 



Tnterosseus dorsalis. — Arises fleshy from the opposite faces of 

 metacarpals II and III ; fibres run to a centrally placed tendon, 

 like the midrib of a leaf, and this is inserted to the base of the 

 second phalanx of digit II. As in Leptoptilus. 



Tnterosseus pcdmaris. — More venti^al and stronger than the 

 foreo'oing muscle but Avith similar origin and arrangement. 



