1869. ] MYOLOGY OF MENOBRANCHUS LATERALIS. 461 
sertion of the subclavius, and is inserted into the upper part of the 
radius. 
Triceps (figs. 3 & 6, T). A large muscle arising from the 
postero-external angle of the coracoid from the outer and inner sides 
of the shaft of the humerus, and, by direct continuation, from the 
latissimus dorsi. It is inserted into the proximal part of the ulna. 
Deeper muscles of extensor surface of right forearm, the extensor longus being 
cut and reflected. 
E. B. Extensor brevis. #.L. Extensor longus. P.@. Pronator quadratus. 
S.L£.1 & S.L.2. Supinator longus. U. Ulnaris. 
The supinator longus (figs. 3, 4, 6, & 7, S.L) appears to be 
double (S. Z. 1, and S. L. 2, figs: 3 & 7), unless the more internal 
part (S. Z. 2) represents an extensor radialis. It arises from about 
the lower third of the humerus, and is inserted into the lower part 
of the outer (or radial) side of the radius. 
Ulnaris (figs. 3 & 7, U). This is a rather bulky muscle passing 
from the distal part of the ulnar side of the humerus downwards to 
the corresponding side of the carpus. 
The pronator teres (figs. 4 & 6, P. 7’) also appears to be double 
(P.T.1 and P.T.2, fig. 6). Both parts extend from the lower 
end of the inner (or ulnar) border of the humerus, and extend 
downwards and outwards to the lower part of the radius. 
Extensor longus (figs. 3 & 7, E.L). This muscle extends from 
the outer (or radial) border of the lower part of the humerus, and, 
expanding as it passes downwards, is inserted into the digits. 
Extensor brevis (figs. 3 & 7, Z..B). This is a very small muscle 
which arises from the radial side of the distal end of the ulna, and, 
passing obliquely downwards and outwards, goes mainly, if not 
exclusively, to the most radial digit. 
Pronator quadratus (?) (fig. 7, P.Q). A small muscle passing 
from the ulna to the radius, obliquely downwards, and situated 
between the ulnaris, the inner part of the supinator longus, and the 
extensor brevis. 
Flexor longus (figs. 4 & 6, F.L). This muscle arises from the 
ulnar side of the lower end of the humerus, and, expanding as it 
asses downwards, is implanted into the digits. 
Flexor brevis (fig. 6, F. B). A small subtriangular muscle which 
