366 Mr. W. P. Pycraft on the 



of dense naked skin, covering the surface of the expanded 

 upper cutaneous surface of the carina sterni." Further, he 

 remarks, " OjAsthocomus is one of those birds in which 

 the pterylosis is not so decisive of its affinities as in many 

 cases, the reason being that so great an amount of the 

 unf Gathered spaces is protected by semiplumes. May 

 not these semiplumes in many instances be degenerated 

 feathers ? This question has never been decided, so far as 

 I am aware." 



In a somewhat extraordinary paper by Dr. G. G.Young (14), 

 we gather the following statements as to the pterylography : — 

 " The young is covered with a light coat of dark brown down.^^ 

 Of the adult he writes : — " The bill .... with black hairs at 

 the base ; . . . . the eyes .... have black eyelashes ; the skin 

 round them and on the neck is light blue, and immediately 

 round the eye and on the sides of the head it is almost naked, 

 having only black hairs and small feathers here and there.''^ 



" Both jaws have a row of tubercles on their inner margin 



that act as teeth There is an atrophied nail on the top 



of the thumb and finger." 



The wing of the nestling is described as " having the fore- 

 arm longer than the arm, and the hand longer than the 

 forearm. The thumb is long and well developed, and has a 

 long well-developed claw ; .... thepointof the wing is tipped 

 with a claw equal in size to that of the thumb ; both the 

 thumb and the finger have the power of ab- and adduction. 

 As soon as the young escape from the egg they creep about 

 with the assistance of these hands, stretching out their wings 

 and digging these claws into, or hooking on to, whatever 

 they meet . . . ." 



Mr. Beddard (1) has written the most exhaustive account 

 of the pterylosis of Opisthocomus hitherto published, com- 

 mencing, as he does, with the adult and ending with the 

 embryo. 



In the adult, Mr. Beddard says, ''the ventral surface is 

 covered with a continuous feather-tract as far down as about 

 halfway between the fore and hind limbs ; after this there 

 is a median bare space of some extent, which is, however. 



