214 Zooloyical Society. 



development than has hitherto been met with in the class of Birds — 

 a condition which is evidently connected with the peculiar thickness 

 of the integument, and probably with the burrowing habits of the 

 present species, which possesses in this structure the power of 

 shaking off the loose earth from its plumage, while busy in the act 

 of excavating its chamber of retreat and nidification. 



Constrictor colli. — The whole of the neck is surrounded by a thin 

 stratum of muscular fibres, directed for the most part transversely, 

 and extending from an attachment along the median line of the skin 

 at the back of the neck, to a parallel raphe on the median line of the 

 opposite side : this muscle is strongest at its commencement or 

 anterior part, where the fibres take their origin in a broad fasciculus 

 from the outer part of the occipital ridge ; these run obliquely down- 

 wards and forwards on each side of the neck, but are continued 

 uninterruptedly with those arising from the dorsal line of the skin 

 above mentioned ; the direction of the fibres insensibly changing 

 from the oblique to the transverse. The outer surface of this 

 muscle is attached to the integument by a thin and dense layer of 

 cellular tissue, devoid of fat ; the under surface is more loosely con- 

 nected with the subjacent parts by a more abundant and finer cellu- 

 lar tissue. 



Use. — To brace the cervical integument, raise the neck feathers, 

 and in combination with the following muscle to shake these parts. 

 Sterno-cervicalis. — Origin. Fleshy, from the posterior incurved 

 ])rocess of the sternum, from the ensiform prolongation and middle 

 line of the outer and posterior surface of the same bone. Insertion. 

 The fibres pass forward, and diverging in gently curved lines, ascend 

 upon the sides of the broad base of the neck, and are inserted by a 

 thin but strong fascia into the median line of the dorsal integument. 

 This muscle is a line in thickness at its origin, but becomes thinner 

 as it expands ; the anterior part is covered by the posterior fibres of 

 the constrictor colli. 



Use. — To retract the skin of the neck, and brace that portion 

 which covers the base of the neck ; when these are the fixed points, 

 it win depress and protract the sternum, and thus aid in inspiration. 

 Obs. — In its position and the general course of the fibres, this 

 muscle is analogous to that which supports and assists in emptying 

 the crop in the common fowl ; but the oesophagus presents no par- 

 tial dilatation in the Apteryx, and the situation of the crop is occu- 

 pied by a large mass of fat enclosing one or two absorbent glands. 



Sterno-maxillaris. — 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. Ins. It passes di- 

 rectly forwards along the under or anterior part of the neck, expand- 

 ing as it proceeds, and gradually sejiarating into two thin symme- 

 trical fasciculi, which are insensiijly lost in the integument covering 

 the throat and the angle of the jaw. It adheres 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 



