Zoological Society. 215 



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 immediate office 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-mastoid is 

 represented by the sterno-maxillaris in the Apteryx, the only bird in 

 which this muscle has hitherto been described. 



Dermo-transversalis . — The skin covering the dorsal aspect of the 

 lower two-thirds of the neck, besides being acted upon by the con- 

 strictor colli, is braced down by a thin stratum of oblique and some- 

 what scattered fibres, which take their origins by fasciae attached to 

 the inferior transverse processes of the sixth to the twelfth cervical 

 vertebrae inclusive ; the fibres pass obliquely upwards and back- 

 wards, and are inserted by a thin fascia into the median line of the 

 skin, covering the back of the neck. 



Platysma myoides. — 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. — Origin. By a thin fascia from the ends of the 

 spinous processes of the three anterior dorsal vertebras. Ins. The 

 fibres slightly converge to be attached to the integument covering 

 the scapular region. 



Dermo-iliacus. — Origin. Fleshy, from the anterior margin of the 

 ilium. Ins. The fibres pass forwards and slightly converge to be in- 

 serted into the scapular integument. 



Dermo-costalis . — A muscle resembling the preceding in form. 

 Origin. Fleshy, from the costal appendages of the seventh and 

 eighth ribs. Ins. The fibres pass forwards and join those of the 

 preceding muscle, to be inserted into the scapular integument. 



Obs. The three preceding muscles are broad and thin, but well- 

 defined ; they would appear to influence the movements of the rudi- 

 mentary spur-armed wing through the medium of the integument, 

 as powerfully as do the rudimental representatives of the true muscles 

 of the anterior extremity. 



There are also two muscles belonging to the cutaneous series, and 

 inserted directly into the bones of the wing. One of these, the 

 dermo-ulnaris, is a small, slender, elongated muscle, which takes its 

 origin from the fascia beneath the dermo-costalis ; its fibres pass 

 backwards, and converge to terminate in a very slender tendon which 

 expands into a fascia, covering the back part of the elbow joint. 

 Use. To extend the elbow joint and raise the wing. 



The dermo-humeralis is also a long and narrow strip, deriving its 



