YOUNG BIRDS AND RECORDS OF THE PAST 141 



the two appear to be so profound that, judging from the 

 evidence as it stands, one would say that they represent 

 two distinct types, bearing only a general resemblance one 

 to another. The pterygoid and palatine in the emu 

 articulate one with another by overlapping edges, or by 

 " squamous suture," in the gull and fowl by a cup-and- 

 ball joint. The pterygoid and vomer in the emu are in 

 close relationship, in the gull and fowl they are widely 

 divorced. These things Huxley saw, and they persuaded 

 him that the two types, the one common to the ostrich 

 tribe, the other occurring in all other birds, with various 

 minor differences, were entirely distinct. 



A study of the skulls of young birds on which I was 

 engaged a year or two ago showed me that, as a matter 

 of fact, the more specialised type is directly derived from 

 the less specialised, more " primitive," or more ancestral 

 type ; and that all the specialised types of palate attain 

 their several peculiarities only after passing through a 

 more or less extensive series of changes, commencing 

 with a stage which answers, more or less exactly, to the 

 palate of the emu. The nature of the series of changes 

 which affect the transformation from the one type to 

 the other may be gathered sufficiently well from what 

 obtains in the palates of the gull, the fowl, and the penguin. 



In the nestling penguin the palatines have assumed 

 the form characteristic of the " neognathine " — the type 

 wherein the palatines meet in the middle line — but the 

 relations between the pterygoid and vomer are as in the 

 " Palaeognathine " palate, though they show an approxi- 

 mation towards the more specialised type. 



Briefly, the pterygoids are rod-shaped, but terminate 

 forwards in a spike which in some individuals reaches 

 the hinder extremity of the greatly reduced, blade-like 



