16 MESSRS. F. E. BEDDARD AND F. TREVES ON THE [Jan. 15, 
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 phalanges, 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. 
Interosset.—TVhere 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 teresting 
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 :— 
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. 
Rhinoceros. 
Ext. comm. digit... Origin:—(1) Extensor con- 
dyle; (2) upper part of 
ulna and radius ; (3) from 
ulnar border of radius to 
halfway down that bone. 
Insertion upon all 3 digits. 
Ext. lat. digit...... 
Ext. obl. met. ...... 
Flexor ext. met. ... 
Origin :—(1) Extensor con- 
dyle; (2) shaft of ulna. 
Ins. (st phalanx of ulnar 
digit and (by a slight ten- 
don) to middle digit. 
Origin by one head trom 
exterior condyle and shaft 
of radius; by 2nd head 
from radius. Jns., radial 
metacarpal. 
Origin from extensor con- 
dyle and olecranon. ns. 
into pisiform. 
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 pisiform; (2) outer 
metacarpal, 
