82 GENERAL ORNITHOLOGY. 



with tegumentary outgroivths, or appendages. These peculiar structures are very light, weigh- 

 ing little in proportion to their bulk ; and some kinds of feathers are very strong and elastic^ 

 easier to bend than to break — in fact, the horny part of a feather is a very tough substance. 

 Feathers make extremely poor conductors of heat, and consequently a warm covering of the 

 body. 



All a bird's feathers, of whatever kind, collectively constitute its ptilosis (Gr. nriKov, jJtilon, 

 a feather) or plumage (Lat. pluma, a plume or feather). In many cases tlie first plumage of 

 the nestling or uewly-hatched bird is a short-lived set of feathers so difi'erent from the crop 

 next grown and longer worn as to give rise to the technical distinction between 



Neossoptiles and Teleoptiles (Gr. veossos, neossos, a young bird, chick, or fledgling ; 

 TeXeos, teleos, finished, final, or mature ; and tttiKov, ptilon, a feather). A neossoptile is an un- 

 finished feather which precedes a final feather, is borne upon the latter for a while, and then 

 drops ofi". All birds do not have neossoptiles, and these temporary feathers form but a sparse 

 and scanty covering of some birds which possess them. Such is the case with those birds 

 which are commonly said to hatch naked, and which stay in the nest until they are fully 

 fledged; though even in these instances the few straggling hair-like feathers which may be 

 first observed are neossoptiles. In the highly exceptional case of the Mound-birds (MegajiO- 

 didce) neossoptiles are shed before the chick is hatched, so that the apparently first but actually 

 second set of feathers are teleoptiles. Neossoptiles are copious enough to form the complete 

 downy covering of those young birds which hatch clothed and are able to run about or swim 

 almost immediately, as in the cases of the chicks, ducklings, or goslings of the poultry-yard, 

 the unfledged young of plovers, snipes, and many others: such a covering is also speedily 

 acquired by various birds which hatch naked or nearly so, yet remain long in the nest, as the 

 squabs of pigeons, and the nestlings of herons, gulls, and most other water-birds. The gen- 

 eralization may be made, that neossoptiles are most copious and conspicuous in the lower 

 orders of birds, as the walkers, waders and swimmers, least so in the higher Passerine and Pi- 

 carian orders. This distinction agrees very well with what are explained beyond as altricial 

 or psilopeedic birds on the one hand, and prcecocial or ptilopcBdic birds on the other hand ; less 

 exactly, with birds called nidicolous and nidifugous, or those which remain some time in the 

 nest and those which can leave it at once. Neossoptiles are always weak, fiufl"y, hairy or 

 downy feathers — in fact, they form the first "downy plumage" of any bird which possesses 

 such a covering. Their character will be better understood by the student after he has read 

 what is said beyond of the structure of feathers. The distinction between neossoptiles and 

 teleoptiles is not that the former are downy, for many of the latter are equally downy ; but that 

 neossoptiles are shed or moulted, from the ends of the teleoptiles upon which they are borne, 

 not from the skin itself. In fine, a neossoptile is simply the temporary, deciduous, terminal 

 portion of an ungrown teleoptile, though it may be the only kind of a feather the young bird 

 possesses. The whole plumage of every adult bird consists of teleoptiles, whose several kinds 

 are described beyond. 



Development of Feathers. In a manner analogous to that of hair, a feather grows in 

 a little pit or pouch formed by an inversion of the dermal or true-skin layer of the integument 

 as well as of the epidermal or scarf-skin layer. This pit is the feather-follicle ; it supports tlie 

 base of a little conical pimple, the feather -papilla, upon which the future feather is to be 

 moulded. The outermost layer of epidermal cells is called the epUrichium ; the subjacent 

 layers form the Malpighian stratum, which enters into the structure both of the follicle and of 

 the feather itself. The cells of this stratum, rapidly multiplying and growing downward into 

 the pit, separate into two sets, one of which lines the whole wall of the follicle, while the other 

 covers a mass of cells which have meanwhile shot up in the centre of the follicle from the 



