Zooloyical Society. 223 



Tliis muscle is a direct inspirator : by drawing down the scapula 

 it depresses the sternum through the medium of the strong coracoi- 

 deum, increases the angle between the vertebrcd and sternal ribs, and 

 dilates the thoracic air-cells. 



Levator scapula. — This seems to be the most anterior portion of 

 the series of muscles which constitute the serratus magnus. Origiri. 

 Two flat fleshy strips from the inferior transverse and costal processes 

 of the last and penultimate cervical vertebrae. Ins. 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. Ins. 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 vertebrae, 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 : che 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. 



Ddtoides. — This is a single long and narrow triangular muscle, of 

 which the base is attached to the conjoined extremities of the scapula 

 and coracoid, 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 closeh' attached to the scapula, and is inserted into the 

 inner and posterior part of the proximal end of the humerus. 



MuscuU pectorales. — The pectoral muscles, which present their 

 feeblest condition and lowest development in the Apteryx, 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. 



