486 ARKIV FÖR ZOOLOGI. BAND 1. 



The bill of the Kiwis has become much elongated and 

 to a certain degree specialised, but on the other band it shows 

 many very primitive features. The nostrils are situated al- 

 most at the extremity of the bill in a similar manner as 

 usually in the reptiles the nostrils are placed near the end 

 of the snout. In this reptilian feature the Kiwi differs from 

 other birds, and it must be an inheritance as it must be 

 rather inconvenient than opportune when the bird bores in 

 the ground in search of worms, grubs and the like. 



In consequence of the prolonged bill the rostrale as well 

 as the labial of either side has become very long. They are 

 quite distinct from each other, but the labials are fused in 

 the median line in front below the rostral. In the nasal 

 groove extends from above the nostril a narrow but quite 

 distinct nasal, but it does not reach the base of the bill. 

 Basally the posterior end of the rostral is embraced of the 

 same element which above has been called internasal and 

 its anterior ends extend angularly on either side between the 

 base of the rostral and the labial. It appears to be horny (to 

 judge from dry specimens) but less so than the bill itself. 

 Its shape is the same as in the Ostrich and the Nandu. The 

 lower rhamphotheca has in consequence of the very long sym- 

 physeal tract a long but quite distinct mentale. The upper 

 margin of the lower jaw is covered by an infralabial shield 

 extending from the tip to the gape. Below this on either 

 side is a submandibular which with its anterior tip at the 

 symphysis is w T edged in between the mentale and the infra- 

 labial but it does not reach much further. Posteriorly it 

 extends as far as the infralabial, but it is there separated 

 from the same by a downy or feathered strip. From this 

 description may be seen that the bill of the Kiwi contains 

 the same elements as the bilis of other »Batitce». It may 

 therefore be concluded that the Apteryges have originated 

 from ancestors of a generalised type which had just as pri- 

 mitive bilis as the ancestors of other »Batitfö». The Kiwis 

 are thus not degen erated flightless Rails as has been suggested. 

 If the Rails and Kiwis have common ancestors the latter 

 have branched off at such an early stage that the birds in 

 question had not yet assumed any ralline features at least 

 with regard to the bill. 



