FEATHERS OF PENGUINS. 3 



disuse, or to blastogenic variation ? In the latter case it would seem that we must 

 assume that the variation must have affected both the parts concerned at the same 

 time — that l)oth must have been included in the same germinal change — but that the 

 outer horny beak-sheath proved more plastic, undergoing transformation at a quicker 

 rate than the underlying osseous parts. 



The podotheca is made up of a series of small more or less hexagonal scales, while 

 the claws are of very cousideraljle size, and show some variation in the matter of shape. 

 In Aptenodytes the middle claw is always very large, and flattened dorso-ventrally, 

 therein contrasting with the outer claw, which appears to be always somewhat com- 

 pressed in shape ; but the inner claw would seem to vary somewhat, in some specimens 

 being decidedly compressed, and in others as markedly depressed. In Pygoscelis, also, 

 the middle and inner claws are flattened, and the outer laterally compressed. In all 

 the other genera, however, the claws are relatively somewhat smaller, and all agree in 

 being laterally compressed. 



In the extent of the webbing of the toes, the penguins present some interesting 

 differences. Thus in Aptenodytes and Pygoscelis the interdigital webs do not extend 

 more than halfway between the toes ; in A. forsteri, indeed, the inner web is almost 

 obsolete. In other genera, however, as in Catarrhactes, Eiidyptida, and Spheniscus, 

 the toes are fully webbed. In all cases tile outer toe has a free fold of skin running 

 along its outer side, just as in many other swimming birds, e.g., Anatidse and some 

 Rallidse. It is to be noticed that while in newly-hatched birds the toes can easily 

 be spread and the webs examined, this is by no means the case with adult birds, wherein 

 the toes apparently lose much of their power of lateral movement. 



The oil gland is tufted. There is a thick underclothing of down feathers, and 

 filo-plumes are present as usual. 



Tlie Structwv of the Feathers. 



There is an almost universal tradition, religiously preserved not only by text-books 

 of comparative anatomy, but even by works devoted entirely to Avian Morphology, to 

 the effect that the feathers of the penguin are scale-like, and by some this supposed 

 fact has been used as an example of one of the connecting links between birds and 

 reptiles. The origin and spread of this myth is difficult to understand. Generally, 

 doubtless, those who described these feathers as scale-like, and reptilian, merely wished 

 to emphasise what they considered — certainly without looking at the structures in 

 question — an accidental or convergent resemblance to scales. Anything more than this, 

 any closer relationship, morphologically, a moment's reflection, having regard to the rest 

 of the anatomy of this particular group, would show to be impossible. 



How then can this misconception have arisen ? What basis is there for its support ? 

 The origin of the tradition as to the scale-like character of the feathers of the penguin 

 is now lost, but it had its rise, doubtless, in the fact that the feathers of these birds are 



