12 



An UDchanged, i. e., fall-colored feather, 

 examined in a fresh state, exhibited the fol- 

 lowing appearance under the microscope. 

 The rhachis appeared, centrally, to be cellu- 

 lar in construction with an enveloping 

 sheath thickly supplied with the black pig- 

 ment matter, the granules arranged in an 

 order suggestive of a streaming movement 

 toward the tip of the feather. At the junc- 

 tion with each barb a small portion of the 

 main system curved upward into the central 

 portion of that member. Proximally this 

 column ended in the modification of the 

 rachis into barbs. The center of each barb 

 of the colored parts of the feathers con- 

 tained a prismatic column, resembling to 

 my eye, a number of bodies set together so 

 as to resemble the nodes and internodes of 

 a bamboo cane. At the distal end of each 

 barb these bodies tapered, and in many 

 cases the extreme joints were separated 

 from the main column. About the blue 

 portions of the feathers, these columns were 

 massed thickly with black matter, the por- 

 tions giving the rusty effects being much 

 less plentifully supplied, and surrounding 

 this central column a transparent envelope 

 of the yellowish stain was present. The 

 barbules of the non-blue area were the color 

 of this sheath but became well supplied 

 with the dark pigment when the blue-pro- 

 ducing area was met with, completely ob- 

 scuring the presence of the stain. The tips 

 of the prismatic columns showed a pale 

 brownish orange color, but gradually as the 

 microscope slide was passed across the stage 

 the color became deeper until when one- 

 half of the length of the barbs had passed 

 before the objective, it appeared deep black. 



The blue area of such a feather gave a 

 good reaction for Zoomelanin (black), for 



