19 
interval. It is a slender slip, placed under cover of the latissimus 
dorsi, which arises from the eighth, ninth, and tenth ribs, a short 
distance external to the line of their angles (and distinctly from 
the dorsal aspect of the chest wall). This runs forwards under 
cover of the latissimus to reach the hinder angle of the vertebral 
border of the scapula. There it crosses the posterior part of the 
insertion of the rhomboid, and is inserted into the dorsal aspect 
of this angle of the bone. At its insertion its fibres are close to 
and parallel with the scapular attachment of the anterior sector 
of the muscle with whose fibres it was evidently in series, consti- 
tuting a retractor scapule muscle. Its nerve supply was from 
the nerve to the serratus. 
There is no separate levator anguli scapule muscle present, the 
serratus as described representing the entire ‘ ¢rachelo-costo- 
scapulur” muscle of Testut.* 
Amongst marsupials the levator scapulae is nearly always lacking as 
a separate muscle, and the serratus is invariably trachelo-costo-scapu- 
lar in its attachments, and is generally a continuous sheet. The 
extent both of its costal and its cervico-vertebral attachment is very 
variable. It isa single and continuous sheet in Koala,t Thylacinus, 
and Phascogale,{ Dasywrus and Phalangista,$ Macropus gig. and minor. || 
Macalister found it in Wombat)| divided into a weak upper part from 
four cervical vertebre and three upper ribs, and a strong lower part 
from the ribs from the fifth to the eleventh, converging to the sub- 
scapular aspect of the inferior angle of the scapula, and a small part 
of the axillary margin. The condition was the same in one specimen 
of Sarcophilus,|| but in another? he found a separable levator anguli 
scap. from the second and third cervical transverse processes. 
In Didelphys** a levator anguli scapulae is wholly or partly separable. 
Cunninghamytyt found “an indication of a division of the serratus in 
Cuscus into a cervical and a costal portion.”’ 
In Dasyurus,t{ although the muscle is continuous, MacCormick 
describes the posterior five costal digitations as converging “‘in a fan- 
like manner, so as to come to a point at the posterior superior angle 
of the scapula, where they are inserted tendinously. The posterior 
edge of the tendon folds round the posterior part of the insertion of 
the rhomboid.” This latter part of the muscle, as well as the de- 
tached posterior sector in Wombat,$§ I take to be homologous to the 
detached posterior slip in WNotoryctes, although the latter is more 
dorsally placed, and altogether beneath the latissimus; ¢.f., also 
Cuvier & Laurillard’s plate of Phal. cavifrons.|||| 
In Echidna the serratus magnus and levator anguli scap. are in- 
separable, forming a thick layer, extending back as far as the fourth 
rib only, or the fifth rib according to Westling.*** 
Meckel+++ describes the serratus magnus in Ornithorhynchus as con- 
*lvi., page 66. + xxviii., page 129, and lxxii. tiv., page 6. § xxxvi., 
page 110. ||xxix., page 155. ‘1 xxx., page 18. **xxxvili., page 478, and 
wis, Pls; 275, fig. 3. thiv., page, 5:, Ti xxxyi., page 110. §§xxix., page 
155. ||| vi. Pl., page 178. ‘Il xxxix., page 383. ‘***lxii., page 13. 
tht xxxviii., page 487, and xxxvii. 
