No. 614] 



THE BLUE ANDALUSIAN 



99 



In cross-section, the pigment granules are seen to be 

 scattered through the cortex of the barb and along the 

 boundaries of the medullary cells. They are not re- 

 stricted to the apex of the barb, as is reported bv Llovd- 

 Jones (1915, p. 472, Figs. 37-39) in the so-called blue 

 pigeon. 



The predominating shape of the pigment granules in 

 feathers from blue Andalusians is round. There may 

 be a few elliptical granules ,^nd occasionally one which 

 can not be classified otherwise than as a rod. These are 

 quite rare, however, and one may carefully scrutinize sev- 

 eral blue-gray feathers without finding any but round or 

 very slightly elliptical granules. These round granules 

 quite frequently appear in straight rows, giving the effect 

 of a string of beads. 



While the granule shape may have an appreciable 

 effect in giving the bluish-gray cast found in blues and 

 blue-splashed, it seems more likely that, as suggested 

 above, the bluish appearance is due to the restriction or 

 arrangement of the pigment. While the condition is not 

 precisely the same as in pigeons, as described by Cole 

 (1914, pp. 324-325) and Lloyd-Jones (1915, pp. 472^73), 

 the optical effect appears to be from essentially the same 

 causes, namely, the clumping of the pigment within the 

 cells, and the reflection from this pigment through more 

 or less transparent layers of keratin. It appears, how- 

 ever, that in the blue Andalusian the contrast between 

 the pigment-free ends of the barbules and the pigmented 

 barbs and barbule-bases is of more importance in produc- 

 ing the bluish effect than is suggested for the pigeon by 

 these writers. 



A characteristic of the typical blue Andalusian not be- 

 fore mentioned is that the contour feathers on the female 

 and the breast feathers on the male present a laced ap- 

 pearance. This results from a black edging on that por- 

 tion of each feather which is exposed when in its natural 

 position. In this part of the feather the barbules on both 

 sides of the barb are alike, being without hooks. The 



