16 



MESSRS. F. E. BEDDARD AND F.TREVES ON THE [Jail. 1 .'i. 



radius, and, becoming tendinous above the wrist, is inserted into the 

 proximal end of the radial metacarpal bone. 



Flexor sublimis {perforatus). — Arises, in common with the flexor 

 profundus, from the flexor condyle. Passes down as a large fleshy 

 muscle ; becomes tendinous at wrist, under annular ligament, and 

 there divides into three small tendons, expanding into sheath at 

 bases of phalnnges, from inner side of which sheath expansions go 

 forward to be inserted into the base of the second phalanx. 



Flexor profundus {perforans) . — This has a similar origin to last 

 described muscle (flexor sublimis). Becomes a very big tendon, and 

 dividing over the metacarpus lower than the above, passes through 

 a thick sheath to the base of the last phalanx. 



Palmaris longus. — This is a muscle which is apparently not 

 described in the Horse, arising by a short thick fleshy belly from the 

 olecranon ; the fleshy part of the muscle is short and is succeeded 

 by a wide and thin tendon which passes into flexor profundus at the 

 wrist. 



Interossei. — There are four interossei muscles. 



The presence of a palmaris longus, if we are right in thus 

 identifying the muscle described above under that name, is interesting 

 for the reason that it does not occur in the Horse, but does in the 

 Tapir. 



The following table shows the resemblances and differences between 

 the Rhinoceros, Horse, and Tapir in the extensor and flexor muscles 

 of the arm : — 



Rhinoceros. 



Ext. comm. digit... Origin: — (1) Extensor con- 

 djle ; (2) upper part of 

 ulua aud radius ; (3) from 

 ulnar border of radius to 

 halfway down that bone. 

 Insertion upon all 3 digits. 



E.Tt. lat. digit. 



Ext. obi. met. 



Flexor ext. met. 



Origiri: — (1) Extensor con- 

 dyle ; (2) shaft of ulna. 

 Ins. 1st phalanx of ulnar 

 digit and (by a slight ten- 

 don) to middle digit. 



Origin hy one head from 

 exterior condyle and shaft 

 of radius ; by 2nd head 

 from radius. Ins., radial 

 metacarpal. 



Origin from extensor con- 

 dyle and olecranon. Ins. 

 into pisiform. 



Horse. 



Origin: — (1) Extensor con- 

 dyle ; (2) humerus below 

 extensor condyle ; (3) the 

 anterior border of external 

 ligament of articulation of 

 elbow ; (4) superior and 

 external tuberosity of 

 radius ; (5) external bor- 

 der of radius. 



Origin. From external tube- 

 rosity of radius and from 

 shaft of radius and ulna, 

 not from humerus. 



Origin. Only one head from 

 external side of radius. 



Insertion by 2 tendons: (1) 

 on to j)isiform ; (2) outer 

 metacarpal. 



