260 Recent Literature. [April 



It is Mr. Millais's discussion of plumage changes in the diving ducks that 

 naturally attracts most attention. He was formerly a strong adherent of 

 the theory of ' aptosochromatism ' — color change without molt — and 

 the reviewer ^ some years ago had occasion to challenge his views on the 

 plumage change of the Sanderhng,^ showing that the feathers that were 

 supposed by Mr. Millais to undergo change of pigment remained unchanged 

 from their emergence from the pin feather sheath until lost in the next 

 molt. 



While Mr. Millais has now in a great measure abandoned his earlier 

 views, he is still loath to relinquish entirely the possibility of direct color 

 change. He speaks of the wearing away of the surface of a feather so as to 

 disclose underlying pigment of a different color as a possible explanation of 

 certain changes, " but," he adds," it does not explain the remarkable ' rise ' 

 of colour that comes with the curly feathers of the tail [of the Mallard] in 

 August. These feathers (which are only renewed once in the year) come 

 in rich brown with a black center. So they remain for a short period, but 

 late in September as they elongate and curl, they begin to turn black until 

 by the end of the month they are jet black. A rise of colour must therefore 

 be in course of movement the whole period as the feather elongates and 

 must prove that there is a means of transmission either through veins 

 or figment [sic] cells of infinitesimal size." While our author quotes Mr. 

 Pycraft in opposition to his views, he makes the rather weak contention 

 that Mr. Pycraft did not use a very high power microscope in his investi- 

 gations, and possibly failed to see the " infinitesimal cells " to which he 

 alludes. He however makes no reference to Dr. R. M. Strong's able 

 paper on ' The Development of Color in the Definitive Feather ' ^ which 

 to our mind dismisses the possibiHty of any change of pigmentation such as 

 Mr. Millais claims and we are inclined to think that the changes which he 

 still attributes to ' aptosochromatism ' will eventually be fully explained in 

 the same manner as were those of the SanderUng. It is in discussing 

 plumage change especially that Mr. Millais shows his lack of familiarity 

 with the pubhcations of American ornithologists; at least he makes no 

 allusion to them. 



The long series of photographs of Eider skins illustrating the molt of 

 this species could we think have been made far more useful if they had been 

 differently arranged. Mr. Millais' method of judging the progress of molt 

 by the date is not satisfactory as the individual variation in plumage on a 

 given date is very great, and few series if any will show a regular gradation 

 if arranged chronologically. 



Apart however from his explanation of some of the color changes that 

 he describes, there is Uttle that calls for criticism in Mr. Millais' beautiful 

 volumes. They form a charming addition to ornithological literature and 



1 Stone, Witmer. Ihis. April, 1901, p. 464. 

 « Millais, J. G. Ibis. October, 1896, p. 451. 

 3 Biill. Mixs. Comp. Zool., XL, pp. 147-186, 1902. 



