16 GENERAL HISTORY OF BIRDS. 



with the base of the shaft of the preceding, and {h) the growth caps of the 

 new feather are continuous with the dead caps in the shaft of the older growth. 

 Actually, the tip and shaft connection and the cap connection are rarely con- 

 tinuous, for the cessation of growth is usually long and the size and weight of 

 the old growth forces its removal which the connections are too feeble to pre- 

 vent. There are cases, nevertheless, where the connection is maintained for a 

 time, as will be shown later. 



The first growth of contour feathers is that known as downs, or more 

 exactly neossoptiles. These are present, or partly grown, at the hatching of 

 the bird, or are absent or nearly so. They do not remain long, for to-day 

 they have no value on most birds, and but a temporary use on others, but are 

 soon forced from the papillae by the next growth, the mesoptile, or, as it is 

 generally known on many birds, especially the passerine, the nesting plumage. 

 On nearly all birds where they now exist, (mostly the higher forms,) the rami 

 of the neossoptiles have their bases, (for they have no rachis or shaft,) bound 

 together by the remains of the sheath within which they were formed, as in all 

 feathers, but a rupture of this sheath ring, (and it is naturally ruptured on 

 most birds,) shows that each ramus of the neossoptile is continuous into each 

 ramus of the mesoptile, or, in rare cases on parts of feathers, the connection 

 is obsolete. There are exceptions as to the ostrich and the duck, where the 

 neossoptile rami unite at their bases to form a shaft the base of which divides 

 into the rami of the mesoptile. Between these growths molt occurs, the dis- 

 connection occuring at varying periods for different feathers of the body, at 

 the weakest point, wherever that may be, either structurally or at the time. 

 On some birds, however, either partially or entirely, the connection is stronger 

 than friction can overcome, so that the neossoptile is lost, if it is lost before 

 the mesoptile is shed, by wearing, either completely or by the loss of the 

 weaker rami. In the totipalmate birds, the neossoptile has a flat generalized 

 shaft which is persistent dermally until forced from the papilla by the growth 

 of the mesoptile, which grows for some time before its weaker pregrowlh is 

 ousted. On the flight feathers, especially in the tropic birds, the ordinary 

 process occurs, thus showing the greater phylogenetic development of those 

 parts. 



While the molt of the neossoptile is usually perfect, there are cases where 

 the neossoptile remains attached to the mesoptile, the base of which is attached 

 to the tip of the succeeding growth, the first teleoptile, but these are not 

 readily found owing to abrasion of the feathers. 



The connection between the shaft of the mesoptile and the tip of the 

 teleoptile is rarely evident because of the greater specialization and longer life 

 of these feathers and the longer molting period. Usually the mesoptile drops 

 out and the tip of the teleoptile soon appears in its place, but sometimes the 



