266 MR. ST. GEORGE MIVART ON [Apr. 22, 
part of the humerus, and is inserted into the same side of the radius 
towards and at its distal end, some fibres seeming to run on to the 
carpus. 
Fig. 2. 
Deeper flexor muscles of right forearm, the fleor Jongus cut and reflected. 
B. Biceps. F. B. Flexor brevis. F.L. Flexor longus. §S. Z. Supinator longus. 
P. T. Pronator teres. 
Deeper muscles of extensor surface of right forearm, the extensor longus cut 
and reflected. 
E. B. Extensor brevis. E. Z. Extensor longus. P. Q. Pronator quadratus. 
S.Z. Supinator longus. U. Ulnaris. 
Ulnaris. A muscle which extends along the ulnar border of the 
forearm (figs. 3 & 4, U), arises from the ulnar side of the lower end 
of the humerus, and is inserted along the corresponding border of 
the ulna. Some fibres coming from the radial condyle of the 
humerus, and fusing with this muscle, doubtless represent the extensor 
ulnaris of higher animals. 
The pronator teres (figs. 2 & 2a, P. T) is a rather large muscle. 
It springs from the lower end of the ulnar border of the humerus, 
and is inserted into about the distal half of the radius. Although a 
wide muscle, only the narrow edge of it is seen before the removal 
of the flexor longus. 
Extensor longus (figs. 2, 3, & 4, H. L). This arises from the 
radial border of the lower end of the humerus, and, expanding as it 
passes downwards, is inserted by fascia into the digits. 
Extensor brevis (fig. 4, 2. B). A subtriangular muscle may 
perhaps be thus named which arises from the distal part of the radial 
side of the ulna and from the carpus, and goes mainly to the radial 
digit. It may perhaps represent the extensor pollicis. 
Pronator quadratus (?) (fig. 4, P. Q). A small muscle passes 
