384 MR. ST. G. MIVART ON THE ANATOMY OF ECHIDNA HYSTRIX. 
This second part arises, by aponeurosis, mainly from the basioccipital, extending 
much further forwards than the origin of the first part. It is inserted into the anterior 
(superior) part of the vertebral margin of the scapula. 
Deltoid (Plate LII. figs. 1 & 2, n1 & p2).—This appears to consist of two parts,—the 
first à triangular muscle, arising from the whole length of the clavicle and lateral 
branch of the interclavicle and from the terminal portion of the acromion: it is 
inserted into the prominence continuous with the greater tuberosity of the humerus, 
external to and rather below the insertion of the pectoralis. 
The second partis a long and narrow muscle, with a long and strong tendon of inser. 
tion. It arises from the anterior vertebral angle of the scapula, and is inserted into a 
depression in the deltoid crest of the humerus, its tendon being implanted in the midst 
of the fibres of insertion of the first-described portion of the muscle. 
Supraspinatus (Plate LII. fig. 2, s.s).—This muscle has a very extensive origin, arising 
as it does from almost the whole of the inner surface of the scapula not occupied by the 
insertion of the serratus magnus. -It is inserted by a strong tendon into the summit of 
the greater tuberosity of the humerus immediately internal to the infraspinatus, with 
which it is, at its insertion, closely connected. 
Professor Owen has pointed out' that the supraspinous fossa is on the inner surface 
of the scapula, through the peculiar development of the spine. In the Ornithorhynchus 
this muscle must be considerably smaller than in the Echidna, owing to the situation 
of the subscapularis in that genus. 
The infraspinatus (Plate LII. figs. 1 & 2, 1.8) arises from the surface of the scapula, 
between the long head of the ¢riceps and the free margin of the spine and acromion 
(the actual anterior margin of the scapula) ; it is inserted into the greater tuberosity of 
the humerus, closely connected with the muscle last described. The muscle in the 
Ornithorhynchus which is figured by Meckel (tab. vii. no. 13), and named by him “ del- 
toides,” appears to be the same as that which I have named infraspinatus in the Echidna. 
Teres minor.—This muscle appears to be wanting in the Echidna, unless it is repre- 
sented by the muscle which I have described as the second part of the deltoid. 
The Zeres major (Plate LIL. fig. 1, T.m) is a small muscle, and is tendinous both at its 
origin and insertion. It arises from the recurved posterior vertebral angle of the scapula, 
and is inserted into the prominent ridge running down from the lesser tuberosity of the 
humerus. This muscle appears to be considerably larger in the Ornithorhynchus de 
Subscapularis (Plate LII. fig. 1, 8).—This large muscle has a most anomalous situation. 
inasmuch as it is confined to the outer surface of the scapula. It arises, indeed, from the 
whole of that outer surface posterior to the origin of the long head of the triceps. n 
inserted into the lesser tuberosity of the humerus by a very strong and wide tendon 
In the Ornithorhynchus this muscle takes origin in part from the outer surface of ine 
scapula, but mainly from its inner face, in the usual mode. 
Dorso-epitrochlear (?) (Plate LIT. fig. 1, D.E).—There is a long narrow muscle arising 
from the posterior extremity of the vertebral margin of the scapula, and from the posterior 
1 . 
Loc. cit, pp. 376 & 381. 2 Meckel, loc. cit. p. 26, tab. vi. no. 15. 
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