31 
serted into the dorsal aspect of the greater or radial tuberosity of 
the humerus between the insertion of the supraspinatus and the 
origin of the “ outer” humeral head of the triceps (fig. 8, 0.tr.). 
In the Marsupials generally, according to Meckel,* the supra 
spinatus is larger than the infra-spinatus. The only exceptions, I 
note, are Macropus bennettut and Koala.t+ 
In the Echidna, Mivart$ describes this muscle as arising from the 
surface of the scapula between the long head of the triceps and the 
free margin of the spine and acromion (the actual anterior margin of 
the scapula) ; and Westling|| figures and describes the same muscle. 
According to Westling, the muscle is innervated chiefly by the Nervus 
axillaris. 
In Ornithorhynchus (McKay) the muscle occupies a much greater 
proportion of the inner surface of the scapula, owing to the ridge for 
the scapular triceps being much nearer the actual posterior border 
than is the case in Echidna. It otherwise corresponds to that in 
Echidna. It is innervated partly from the N. axillaris, but chiefly 
from the N. supracoracoideus (suprascapular nerve). 
M. supraspinatus (figs. 8 and 15, s.s.) arises from the whole 
of the prescapular fossa, as well as from the preaxial border of 
the scapula and the prominent anterior angle of the vertebral 
border. Its fibres form a fleshy mass, which bulges considerably 
beyond the prescapular border, being in apposition with the fibres 
of the rhomboideus dorsally, and of the subscapularis ventrally. 
It passes outwards under cover of the acromion and “meso- 
scapular segment” to be inserted into the proximal facet upon 
the greater (radial) tuberosity of the humerus. 
Neither among Marsupials nor the Eutherian orders specially 
noticed does this muscle present any remarkable features. 
Among Monotremes the muscle arises from the actual inner surface 
of the scapula, owing to the remarkable modification of the scapula in 
this order. (See note by Dr. McKay and the writer in Proc. Linn. 
Soc. N.S.W.)41 
The muscle is supplied by the N. supracoracoideus, which represents 
the suprascapular nerve. 
IM. coraco-brachialis is entirely unrepresented in Votoryctes. 
In no other Marsupial recorded is the coraco-brachialis absent, 
though in Wombat Macalister** describes it as “ extremely small and 
rudimentary,’’ while in several others only the coraco-brachialis brevis 
element is present, eg., Thylacinus,t + Dasywrus,tt and Myrmecobius, 
Chironectes, and Halmaturus.§§ 
In the Echidna the coraco-brachialis system of fibres is extremely 
luxuriant, where it consists of the three distinct elements, which 
Wood|j|| regards as constituting the typical muscle. One of the ele- 
ments is, however, epicoraco-brachial in its attachments. 
* xxxvill., page 499. tiv., page 9. + xxii., page 226, and xxviii., page 
130. §xxxix., page 384, and PI., page 52., figs. 1 and 2, 7.s. || lxii., Taf. ii., 
fig. 5.: ‘lxiv. **xxix., page 160. ttiv., page 10. ttxxxvi., page 118. 
§§ xxvi., page 803. ||| Ixxi., page 45, et seq. 
