W. P. PYCRAFT. 



very close-fitting, stiff, and have flat, thick shafts. Further, the absence in the wing 

 of definable primaries and secondaries, and the extremely small, thick-shafted feathers 

 of the preaxial border of the wing, must have contributed much to the fostering of this 



myth. Founded on slovenly observation, it owes 

 its perpetuation to the practice, unhappily not 

 always avoidable, of accepting statements of 

 earlier writers without reserve or verification. 



There can be no doubt, then, but that the 

 feathers of the penguins have no more likeness 

 to the scales of reptiles than have the feathers 

 of other birds. As in the case of the flightless 

 Struthious birds, the penguin's feathers are 

 unquestionably degenerate, while in some re- 

 spects they appear to have undergone some 

 specialisation. 



This specialisation is apparent in the 

 structure of the shaft, which is curved in such 

 a way that between the body and the outer 

 surface of the feathers there is enclosed a wide 

 space which is filled by down feathers. This 

 forms an effective barrier against the intense 

 cold in which these birds live a barrier which 

 is further supplemented by a thick layer of 

 fat beneath the skin. The curvature of the 

 shaft is peculiar. At the region where the 

 calamus which is extremely short, and dorso- 

 ventrally depressed leaves the skin, it turns 

 sharply upwards, arches considerably, and then 

 passes into the more gently curved rhachis 

 (Fig. 1). This is broad and flat, fading on 

 its ventral surface insensibly into the rami, 

 instead of forming beneath these a more or 

 less quadrangular beam as in more normal 

 feathers. The aftershaft is peculiar in that it 

 consists of a short, flat, flabelliform main axis 

 supporting numerous long, downy rami. 



The lower umbilicus of the calamus is not sharply defined. This is a point of some 

 importance, inasmuch as it would seem to be due to the fact that before the calamus 

 has actually completed its growth, the feather follicle at its base has begun to form the 

 tips of the rami of the succeeding generation, the sheath enclosing which becomes fused 

 with the rim of the umbilicus. 



FIG. 1. MOULTING CONTOUR FEATHER OP EMPEROR 



PENGUIN, Aptenodytes forsteri, SHOWING THE RE- 

 MARKABLE CURVATURE OF THE CALAMUS, AND THE 

 DOWNY AFTERSHAFT (a). 



