610 



PROF. J. COSSAR EWART ON THE 



The relation of the various kinds of fea,the^^s of mature birds to 

 Jiestlhig feathers is indicated in the following table : — 



I'apillte. 



Filaraenta 

 (Cryptoptiles). 



Prefiloplumse 

 (Prefilopennfe) 



I. Prepeiinaj 

 (Protoptiles). 



II. Prepennse 

 (Mesoptiles). 



Prepluniulae. 



Filopiumafi 

 (PilopennaB). 



Plnmose PeiiiiaB 

 (Metaptiles). 



Pennaceous Peiinas 

 (Teleoptiles). 



Plumules. 



1. The Prepennce. 



The most concise and authoritative statement I have come 

 across about nestling feathers occurs in ' ISTewton's Dictionar}'- of 

 Birds.' It is there stated that neossoptiles {i. e. protoptiles) " are 

 characterized by (1) a very short calamus, (2) an insignilicant or 

 ill-defined rhachis — if there be one at all, (3) the almost universal 

 absence of cilia, (4) long and slender rami (barbs), and (5) the 

 absence of an aftershaft except in Dromreus " ; in another para- 

 graph it is stated that the barbules (radii) of the aftershaft have 

 no cilia (2). A more recent statement about neossoptiles is that 

 the feathers forming the familiar coat of newly hatched ducklings 

 and chicks are not protoptiles but mesoptiles, and hence corre- 

 spond to the feathers forming the long fur-like second coat of 

 Penguins (3). 



I may at once state that in Mallard ducklings the outer 

 nestling coat consists of typical protoptiles characterized by 

 (1) a well-developed calamus which may contain over twenty 

 " cones," (2) a well-developed rhachis, (3) well-developed and in 

 some cases hook-like cilia, (4) short stiff, as well as long slender 

 barbs, and (5) by a well-developed aftershaft, the barbules of 

 which bear cilia. 



In ducklings the protoptiles vary in size — some are over 30 mm. 

 in length and resemble plumose (metaptile) feathers, others are 

 uiider 10 mm. in length and resemble preplumulpe. But the 

 small as well as the large protoptiles consist of a calamus, a shaft, 

 and an aftershaft. In addition to assisting the preplumulfe, and 

 later the plumulfe, in diminishing the flow of heat from the skin, 

 the protoptiles, as a rule, prevent water reaching the under coat 



