白色レグホーン,プリマスロツクおよびその一代雑種の羽毛発生の比較

Abstract

The early development of the down feathers was investigated in White Leghorns, Plymouth Rocks, and their hybrid from a morphological point of view.In White Loghorns, the rudiments of the feather appear at about 10 or 11 days of incubation. The first indication of feather formation is an upward growth of the dermis and the consequent production of a papilla. As the papilla grows, it projects over the surface, with its base becoming embedded more and more deeply in the dermis. Five successive stages of the growth of a feather are shown in Figs. 2 to 6.The manner of feather formation in Plymouth Rocks is essentially the same as that in White Leghorns, though numerous melanophores appear in the inner layer of the epidermis (Figs. 7 and 9). Some of the typical melauophores are shown in Fig. 11.In the hybrid (White Leghorn _??__??_ ×Plymouth Rock _??__??_), melanophores also appear in the inner layer of the epidermis, but are rery small in number as compared with the case of Plymouth Rocks. Each melanophore is loosely packed with melanin granules (Eig. 12).