SHANK COLORS IN DOMESTIC FOWL. 239 



ployed. Though many fixing solutions and stains were tried, 

 generally with satisfactory results, the best sections were made 

 by the use of formalin, hematoxylin, eosin, and Sudan III. 



The External Structure of the Shank. 



A brief review of the structure of the external shank will 

 not be out of place. The outer layer of the epidermis is modi- 

 fied into scales, which vary in size, according to their location 

 on the leg, and the breed of the bird. Two well-defined rows 

 of scales cover the anterior portion in most varieties (2). That 

 row which is located nearest the mid-line usually has the largest 

 scales. These in some cases have a length of one cm. and a 

 breadth of 1.5 cm. Their shape is imperfectly quadrilateral, 

 with the corners slightly rounded. In some birds the arrange- 

 ment is irregular, and their shape may vary from round to 

 polyhedral. Adjoining the large scales on both sides of the 

 shank are two or three rows of smaller incompletely developed 

 ones, in shape more oval than quadrilateral. On the posterior 

 side we again find two rows similar in size to those on the ante- 

 rior part. But, as Reichenow (12) has pointed out, "Ueber- 

 gange zu den vorigen Formen entstehen, indem die beiden 

 vorderen Reihen von Quertafeln verschmelzen, oder die 

 hinteren in kleine Schilder sich auflosen, oder die kleinen 

 Seitenschilder auch noch zu Quertafeln verwachsen." In the 

 larger scales there is an imperfect adhesion to the^under-lying 

 epidermal layer, save at the upper edge and along the sides. 

 The lower edge which is free touches the scale below, and, in 

 the birds studies, over-lapped it for a distance of perhaps a 

 tenth of a centimeter. Jefifries (4), however observed no such 

 over-lapping. The small lateral scales are attached to the under 

 epidermis throughout. 



Histology. 



The skin of the bird, Hke that of all vertebrates, consists of 

 two layers ; the outer or epidermis, and the inner or corium, 

 cutis, or dermis (2). 



