32 
deum, increases the angle between the vertebral and sternal ribs, and - 
dilates the thoracic air-cells. ’ 
Levator scapule.—This seems to be the most anterior portion of 
the series of muscles which constitute the serratus magnus. Origin. 
Two flat fleshy strips from the inferior transverse and costal processes 
of the last and penultimate cervical vertebre. Jns. Into the inner 
and upper side of the middle third of the scapula. It depresses as 
well as draws forwards the scapula, and thus aids the serratus in the 
action of inspiration. 
Serratus anticus minor.—Origin. From the outer part of the costal 
process of the sternum. Jns. Into the posterior part of the base of 
the coracoideum. 
Trapezius.—This flattened oblong quadrilateral muscle arises from 
the fascia, extending upon the back from the spinous processes of 
the posterior cervical vertebre, and is inserted into the conjoined 
extremities of the scapula and coracoideum. 
There is no representative of the rhomboidei. 
Latissimus dorsi.—This muscle consists, as usual in Birds, of two 
portions, both of which have their origin from a continuation of the 
fascia (attached to the dorsal spines) which also gives origin to the 
trapezius: the fibres of the smaller and anterior slip converge to 
their insertion: the fibres of the posterior and broader strip are 
slightly twisted, the posterior edge being folded inwards as they also 
converge to join the preceding, and to be inserted with it into the 
posterior and inner side of the proximal extremity of the humerus. 
Deltoides.— This is a single long and narrow triangular muscle, of 
which the base is attached to the conjoined extremities of the scapula 
and ccoracoid, and to the capsule of the shoulder-joint; the apical 
insertion is into the upper and outer third of the humerus, which this 
muscle directly raises. ; 
Infraspinatus.—A muscle which may be compared either to the 
infraspinatus or teres major comes off from the lower margin of the 
anterior two-thirds of the scapula, passes behind the shoulder-joint, 
where it is closely attached to the scapula, and is inserted into the 
inner and posterior part of the proximal end of the humerus. 
Musculi pectorales.—The pectoral muscles, which present their 
feeblest condition and lowest development in the Apteryz, are never- 
theless similar in number and arrangement to those which in some 
birds of flight are known to outweigh all the other muscles of the 
body. 
The pectoralis major is represented by two very thin triangular 
layers of muscular fibres, the anterior of which is three lines broad 
at its base, and is attached to the sternum immediately exterior to 
the perforation of that bone: the second, posterior, and somewhat 
narrower portion, rises immediately behind the preceding, from the 
osseous bridge separating the perforation from the notch; the two 
portions converge as they extend upwards and outwards to unite 
and be inserted into the anterior and internal surface of the proximal 
third of the humerus. 
The pectoralis medius seu secundus is a similar, thin, feeble, but 
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