45 
that which supports and assists in emptying the crop in the common Fowl; but the 
cesophagus presents no partial dilatation in the Apterya, and the situation of the crop 
is occupied by a large mass of fat enclosing one or two absorbent glands (Pl. XIII. a’). 
Sterno-mavillaris (Pl. XIU. 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. Fleshy ; 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 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-mastoideus is represented by the sterno-mavillaris in the Apterya. 
Dermo-transversalis (P|, XIII. 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 origins by 
fascive attached to the inferior transverse processes of the sixth to the twelfth cervical 
vertebre 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 myoides (P|. X. 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 (Pl. X. f).—Origin. By a thin fascia from the ends of the spinous pro- 
cesses of the three anterior dorsal vertebrae. Ins. The fibres slightly converge to be 
attached to the integument covering the scapular region. 
Dermo-iliacus (Pl. X. g),—Origin. Fleshy, from the anterior margin of the ilium. 
Ins. The fibres pass forwards and slightly converge to be inserted into the scapular in- 
tegument. 
Dermo-costalis (Pl. X. h).—A muscle resembling the preceding in form. Origin. 
Fleshy, from the costal appendages of the seventh and eighth ribs. Ins. The fibres 
G2 
