XVI 



(pi. xxxii. figs, a, b) which represents a section through 

 the feathers of a Duck's wing, in which every dorsal covert 

 (coloured yelloiv) is connected by a membrane to the shaft 

 of each consecutive iiight-feather, lying proximal to it. 



The accessory plume which we have spoken of above as 

 '^ vestigial " was cousidered by Mr. Wray (and so figured 

 by him) as the proper major covert of the Ist metacarpal 

 remex. Our disputed '' covert " having been included by him 

 in the median series, thus disappears, for the moment from 

 our argument, which now deals with the major coverts only. 

 Had not ^Ir. Wray thus accounted for the function of this 

 vestigial plume, this 1st metacarpal remex must have gone 

 without a covert at all. 



Having had a suspicion that there might have been some 

 misapprehension on the part of Mr. Wray as to the con- 

 nection of the metacarpal remiges and their respective coverts, 

 I next made experiments on sections of the wings of young 

 Sparrows and Fowls under the microscope. This study clearly 

 revealed to me a diflFerent correlation of the major coverts 

 and the remiges in the metacarpo-digital portion of the 

 wing. The microscopical sections (fig. 6j, after correction. 



Fig. 6. 



Dc ^a 



\5tJ^-SL5 'V5^: ■£>" ^ '-.£) ^.*; \2ii ^-2i ^S) '^ r ^^ ^ 



Rci. ' ■' ; ;' \ '\ /' i 



',.' '^ ; ; \ •' Ca. 



Md.-i. \ / 



^licro.scopical section of the wing of a youug bird showing the 

 rekxtive positions of the coverts and remiges. 

 ADD.ii. Addigital remex. Co. Carpal covert. C.n. Carpal 

 remex. Mce. Metacarpal remex. Md.k. Middiuital remex. 

 Pd.r. Predi^ital remex. Rcl. Kemicle. D.c. Dorsal coverts. 

 V.c. Ventral cuverts. 



