16 



found to contain a te8ticle,while the opposite 

 portion of the body possessed an ovary, and 

 Professor Beddard writes that this curious 

 abnormality had been noticed before. 



As no vascular connection appeared to be 

 present in the perfect feathers of my bird, 

 the change appears to be one of internal 

 activity in the feathers themselves, and the 

 simile before mentioned, of the autumn leaf» 

 appears to be still more strongly consistent. 

 The change is none the less vital, however, 

 and ceases with the death of the organism. 

 No tests delicate enough were applied to 

 determine if new matter was formed di- 

 rectly in the feather. It appeared prob- 

 able that none was, but that the striking 

 change depended upon the massing of the 

 dark granular matter from the rhachis to 

 the barbs and their appendages. The ab- 

 sence of definite data upon the chemistry 

 of animal pigments makes remarks in a 

 qualitative direction wholly undesirable. 



To conclude our microscopic study, how- 

 ever, we maj^ affirm : (1) that microscop- 

 ically as well as macroscopically an appre- 

 ciable Aptosochromatic change took place 

 in the individual feathers of my Fasserina 

 cyanea; (2) that this change far from being 

 analytical or retrograde was inclined to the 

 nature of constructive synthesis, probably 

 passive in nature ; (3) that the change was 

 definite as shown by comparison with the 

 blue areas of unchanged feathers; (4) that 

 it depended chiefly upon the gain of dark 

 pigment in the vicinity of the prismatic 

 column, and (5) that there was an appre- 

 ciable difierence in the amounts of blackish 

 pigment supplied to the barbs and barbules, 

 before and after the change. 



F. J. BiRTWELL. 



Albuquerque, New Mexico. 



