MR. E. DEGEjN" on ECDTSIS. 349 



statements made by this author under the different chapters. Allen has criticized it 

 in a general way. 



Amongst the principal dissentients from the la^ys formulated by Schlegel respecting 

 the season, manner, degrees, and methods of moult and alleged changes of colour 

 without moult, should be mentioned, as the foremost, Homeyer, who in ' Rhea,' ii. 

 1S46, p. 157, published some remarks ; he also replied to Schlegel in a communication 

 to ' Naumannia ' (185o), and further by numerous comments on this subject (see 

 Bibliography, 30, 30 «, 31). 



To the most prolific writers of that period who subjected the seasonal and other 

 changes to a fuller scrutiny, unquestionably belongs Brehm (6, 7, 8, 9, & 10) by 

 reason of a large amount of material gathered for this purpose by his son Alfred. 

 However, apart from the profusion of a priori argument and some other additional 

 information, his inquiries had to a great extent the object of refuting the " thesis " laid 

 down by Schlegel, and also similar views held by Martin (32, i^ii)- 



Important contributions to the knowledge of the chemico-physical changes in the 

 feather-structure itself were those of Altum (2), Meves (34), and Bogdanow. Mean- 

 while the question gave rise to a number of minor contributions, consisting of critical 

 remarks or casual observations on the subject, such as those of Gloger (24, 25, 26), 

 Hesler (28), Bock (5), Dwight (18), v. Miiller (36), Gatke (22), Cabanis, and many others. 



Until the appearance of the translation from the Swedish of Sundevall's work (43), 

 a great deal of confusion existed in regard to a scientific knowledge of the topography 

 of the feathering in birds. Sundevall has done much to remedy this deficiency, and 

 confined his researches largely to this character, though principally to the serial values, 

 of the feathers on the wing. 



It is from this point that the researches conducted into the derivation of the 

 plumage began in earnest, as Nitzsch's ' Pterylography,' which appeared in 1840, 

 seems to have been little known or appreciated by his own countrymen, and it was not 

 until the able translation into English, published in 1867 by Dr. P. L. Sclater for the 

 Ray Society, was available that its worth became generally recognized. And in reading 

 Nitzsch, it is not a little remarkable to find that the portion dealing with the covert- 

 feathers on the wing should have received so little attention. Nevertheless, it is to the 

 last-named authors, Sundevall and Nitzsch (37), that we are primarily indebted for a 

 beginning of the study of the morphological question concerning the feathering of 

 the wings of birds. 



After this, with the exception of two short papers in 1856 by Dr. Weinland — one in 

 Journ. f. Ornith. iv. pp. 125-129, and the other in Proc. Boston Soc. Nat. Hist. iv. 

 (1856-59j pp. 34-37, — a period of calm set in, which was broken only by the important 

 work published in 1866 by Dr. Fatio (19), who had meantime conducted a series 

 of investigations into the changes of the plumage, both chemico-physical and physio- 

 logical. To this memoir I have been frequently indebted. 



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