IQ2 Recent Literature. I April 



the work under review. In his account of 'Modes of Plumage Changes' 

 is an erroneous interpretation of the change of color in the young 

 Arizona Hooded Oriole, the conclusion being reached that the "transition 

 in this species is by an addition of pigment without moult." With part 

 of the same material in hand that formed the basis of Mr. Keeler's con- 

 clusion, and much more of similar character representing a large number 

 of other species, it is evident that he has misunderstood the facts in the 

 case, — namely, that a common mottled transition stage of plumage has 

 been mistaken for an actual change of color without moult It is evident 

 that this mottled phase of plumage, occurring in a very large number of 

 species, is a permanent one for the time being, varying greatly in differ- 

 ent individuals of the same age, and not a gradual color change without 

 moult. This, of course, is not proof that there is never any change of 

 color without moult, the only satisfactory proof of which, however, must 

 obviously be based on observation of the living bird for a sufficient period 

 to determine the nature of the change of color. Under 'General Princi- 

 ples of Color in Birds,' we are at a loss to see why the pigment should be 

 considered any more a "product of waste" than the feathers themselves, 

 or other portions of the integument. Mr. Keeler calls attention to "a 

 curious parallelism between the colors" in species of Pipilo and Seto- 

 phaga (p. 147), "which may be only a coincidence or may be a matter of 

 profound significance." This being the case, how about similar parallel- 

 isms between these genera on the one hand and others in Australia, 

 India, Africa, and South America? Or the cases of almost exact parallel- 

 ism in pattern of coloration, and often even in color, of wholly unrelated 

 genera in widely separated parts of the world, which occur over and 

 over again in a considerable number of very distinct styles of colora- 

 tion ? The Pipilo style, the Junco style, the Sturnella style, the Icterus 

 style, the Mimus style, and so on, occur over and over again among Old 

 World birds ; certain African Weaverbirds repeat the red shoulder spots 

 of Age la /us, etc., while in other cases this same marking is repeated in 

 blue, white, or yellow. 



There is space to notice very few of the striking generalizations that 

 occur so frequently in the second third of the book, but a few may be 

 cited in illustration of the general criticism we are forced to make upon 

 Part II as a whole. From reading pages 159-161 one would infer that 

 the feather first grew to its proper size and form and was then decorated 

 by the subsequent deposit of pigment, for we read : "Pigment is a definite 

 chemical substance which travels through the various branches of the 

 feather, advancing farthest and most rapidly along the lines of least 

 resistance and accumulating in masses where the resistence is greatest. 

 Now the pigment cells must reach the various parts of the feather by 

 way of the shaft, and we should a priori expect to find that the resistance 

 would be least right down the shaft. It might spread out a very short 

 distance on the barbs, but the main tendency would be toward the tip." 

 Again he says (p. 177) : "It is evident that along the line of demarcation 



