496 STRUCTUKE AND CLASSIFICATION OF BIRDS 



there is a ventral apterion in the sternal region and a lateral 

 apterion outside each half of the ventral tract. The adult 

 ostrich has a claw on each of digits I. and II. The arrange- 

 ment of the vsdng feathers has been carefully worked out by the 

 late Mr. Wkat.^ He finds the remiges to be quite distinct, 

 as well as the tectrices majores ; the tectrices mediae are but 

 scantily represented, and there is an incomplete row of 

 tectrices minores. The number of remiges upon the hand, 

 including one upon the carpus, is sixteen. There are four 

 to the ala spuria. The number of cubitals is about twenty. 

 It has, therefore, more primaries than any bird except the 

 penguin. 



The genus Apteryx, entirely confined to New Zealand, 

 consists of three or four species, viz. A. australis, A. Mantelli, 

 A. Oweni, A. Haasti, and A.BuUeri. 



It has been described as possessing a continuous, un- 

 interrupted plumage ; but this, according to T. J. Paekee,''* 

 is far from the truth. ' In a fresh specimen of A. Bulleri,' 

 he remarks, ' I find the lateral apterium to be fully 2 

 cm. wide, and to extend about 5 cm. cephalad and 9 cm. 

 caudad from the axilla, its total length being, therefore, 

 about 14 cm. In the same specimen the ventral or inferior 

 space was of about equal width (2 cm.), and extended about 

 11 or 12 cm. caudad from between the origins of the wings. 

 Moreover the inner (ventral) surface of the wing is always 

 nearly devoid of feathers and so constitutes a well-marked 

 lower wing-space.' 



The oil gland is present and the feathers have no after- 

 shaft. 



The relatively minute wing of the Apteryx has a true 

 alar membrane, which, as Paekee has justly pointed out, is 

 further evidence for regarding this bird as the derivative of 

 a flying form. 



p. 121, and Zandeb, ' Uber das Gefieder des afrikauischen Strausses,' Schr. 

 phys.-Sk. Ges. Konigsh. xxix. 1889, SB. p. 31. 



' ' On some Points in the Morphology of the Wings of Birds,' P. Z. S. 1887, 

 p. 343. 



2 'Observations on the Anatomy and Development of Apteryx,' Phil. Trans. 

 1891. 



