OF THE SOUTHERN APTERYX. 279 



that which supports and assists in emptying the crop in the common Fowl ; but the 

 oesophagus presents no partial dilatation in the Apteryx, and the situation of the crop 

 is occupied by a large mass of fat enclosing one or two absorbent glands (PI. XXXIV. a'). 



Slerno-maxillaris (PI. XXXIV. c). — This muscle appears at first view to be the anterior 

 continuation of the preceding, but is sufficiently distinct to merit a separate description 

 and name. Origin. Flesiiy ; from the anterior part of the middle line of the sternum. 

 Insertion. It passes directly forwards along the under or anterior part of the neck, expand- 

 ing as it proceeds, and gradually separating into two thin symmetrical fasciculi, which are 

 insensibly lost in the integument covering the throat and the angle of the jaw. It ad- 

 heres pretty closely to the central surface of the constrictor colli, along which it passes 

 to its insertion. 



Use. — To retract the fore-part of the skin of the neck, and also the head. Each lateral 

 portion acting alone would incline the head to its own side : the whole muscle in action 

 would bend the neck ; but the movements of the head and neck are more adequately 

 and immediately provided for by the appropriate deeper-seated muscles, and the imme- 

 diate ofiice of the present muscle is obviously connected with the skin. Nevertheless, 

 in so far as this muscle acts upon the head, it produces the same movements as the 

 sterno-mastoideus in Mammalia ; and it is interesting to observe, that in the long-necked 

 Ruminants (as the Giraffe) the sterno-mastoid muscles arise by a common origin, and 

 the insertion is by an extended fascia into the angles of the jaw : I consider, therefore, 

 that the sterno-mastoideus is represented by the sterno-maadllaris in the Apteryx. 



Dermo-transversalis (PI. XXXIV. fig. I. d).— The skin covering the dorsal aspect of the 

 lower two-thirds of the neck, besides being acted upon by the constrictor colli, is braced 

 down by a thin stratum of oblique and somewhat scattered fibres, which take their ori- 

 gins by fascise attached to the inferior transverse processes of the sixth to the twelfth 

 cervical vertebrie inclusive ; the fibres pass obliquely upwards and backwards, and are 

 inserted by a thin fascia into the median line of the skin, covering the back of the neck. 



Platysma my aides (PI. XXXI. e). — The representative of this cutaneous muscle is a thin 

 triangular layer of muscular fibres, taking their origin from the outer side of the ramus 

 of the jaw, and diverging as they descend to spread over the throat, and meeting their 

 fellows at a middle raphe of insertion beneath the upper larynx and beginning of the 

 trachea, which they thus serve to compress and support. 



Dermo-spinalis (PI. XXXI. /). — Origin. By a thin fascia from the ends of the spinous 

 processes of the three anterior dorsal vertebrae. Ins. The fibres slightly converge to 

 be attached to the integument covering the scapular region. 



Dermo-iliacus (PI. XXXI. g). — Origin. Fleshy, from the anterior margin of the ifium. 

 Ins. The fibres pass forwards and slightly converge to be inserted into the scapular in- 

 tegument. 



Dermo-costalis (PI. XXXI. h). — A muscle resembHng the preceding in form. Origin. 

 Fleshy, from the costal appendages of the seventh and eighth ribs. Ins. The fibres 



2p2 



