34 
which is inserted with it. Humphry* found it arising from the fore 
part of the coracoid. 
In Pholidotus+ it is a simple gleno-ulnar muscle. 
In Bradypus tridactylus} it is radial in insertion, and it has a glenoid 
and a humeral head of origin, while Humphry; found a third slip 
arising from the coracoid, and Meckel§ found a slip from the deltoid. 
Among the Insectivora there is almost always only a glenoid head. 
The muscle is ulnar in its insertion in Gymmura,|| Erinaceus, and 
Chrysochloris,1 radial in Talpa,** and radio-ulnar in some others. In 
Talpa** it is a very considerable and curiously modified muscle. 
In the Rodents usually only a glenoid head is present, usually in- 
serted into the ulna. It is, however, gleno-radial in e.g. Erethizon.++ 
It is generally gleno-radial in Carnivora. 
M. brachialis anticus, s. internus (figs. 6, 8, and 10, b.a.), arises 
from the concave outer surface of the shaft of the humerus, ex- 
tending as far up as the region of the neck. Here an oblique 
line separates it from the proximal part of the origin of the 
“outer” humeral head of the triceps (fig. 8, o¢.7.), whose fibres 
in this region encroach upon the outer surface of the neck of the 
bone, extending dorsally to the base of the radial tuberosity, and 
thus separating brachialis anticus from infra-spinatus. Below the 
oblique line mentioned the brachialis anticus is separated from 
the triceps by a continuation upwards of the supinator crest of 
the humerus. Fibres of the muscle also arise from the concave 
inferior and outer aspects of the preminent delto-pectoral ridge 
(fig. 8, d.p.tub.). 
The muscle is inserted into the sharp ridge leading distally 
from the coronoid lip of the humero-ulnar articulation, which hes 
in close apposition to the head of the radius. 
In Thylacinustt the muscle arises from the posterior aspect of the 
shaft of the humerus by a linear origin, covered by the outer head of 
the triceps, though separated from it by a well marked external inter- 
muscular septum. It merely clothes the outer aspect of the bone. 
In Cuscus and Phascogale,t~ however, its fibres arise from the outer 
side of the shaft. 
In Dasyurus§ § its origin is from both “ posterior and anterior surfaces 
of the humerus,” extending internally as far as the inner border of the 
bone, and externally as far as the insertion of the deltoid. Posteriorly 
it extends as high as the origin of the outer head of the triceps, which — 
separates it from the teres minor insertion. 
In Wombat|||| the muscle was ‘“‘as usual, in position and attachments, 
winding round the bone below and external to the deltoid crest, lying 
in a deeply excavated sulcus in the humerus.”’ Macalister states that 
“its position is similar in Sarcophilus, the Bandicoot, Opossum, 
Phalanger, Bennett’s and Giant Kangaroo.”’ || || 
*xxi., page 300. + xxvii., page 246. +xxii., page 37. § xxxviil., 
page 520. || viii., page 395. ‘I xxvi., page 799. **xi., page 215. TT xli., 
page 282. tfiv., pagell. §§xxxvi., page 120. ||| xxix., page 161. 
