ME. E. DEGEN ON ECDTSIS. 879 



being graduated in length of growth, a condition which corresponds with that of their 

 corresponding flight-feathers. This first grouping arrangement is well defined in 

 all the specimens of birds of the second season and upwards. 



Stage II. Group-moulting of various degrees of development. 



1. Consisting of formation of previous Group (I.) with the remainder of coverts (0-7) 



renewing from 7-1 (0) in outward direction. (See Table IV. fig. 1.) 



2. Consists of coverts (0) 1-4, or Group II., renewing in an inward direction. All 



the feathers of this second group are either equal in length or partly in graduated 

 condition of development. In the latter case they are supplied from without 

 inwards. (See Table IV. fig. 2.) 



3. Consists of coverts 5-7, forming Group III. The feathers belonging to this 



third group at this stage appear still simultaneously {cf. diagr. Table IV. fig. 3). 

 (Feathers in nascent condition of development.) 



The first degree is common to all individuals, both young and old, and particularly 

 clearly defined for Group I. in specimen No. 4, as quoted already. (Table IV. fig. 1.) 



The second degree is represented by specimen No. 2, more particularly so for the 

 right wing ; by No. 6, left side ; and No. 14 on both sides. {Cf. Table IV. figs. 2, 3.) 



The third degree of this stage of moult, represented in diagram by specimen No. 19 

 (see Table IV. fig. 3), occurs on right side of specimen No. 5, both sides of Nos. 9 

 and 15, and on the right-side M'ing of No. 23. In the latter specimen we have a 

 remarkable combination of two cases of transition from one stage to another by its 

 left-side wing already adopting the more advanced condition of the fully adult 

 individuals of the last, or 



Stagk III. In which the main dorsal coverts follow the same perfected group-arrange- 

 ment of moulting in synchronism and in the identical order of appearance as their 

 respective remiges. This condition is shown in the diagrams by specimen No. 24. 

 (See Table IV. fig. 4.) 



This last stage is achieved only by the oldest individuals, and is attained by the 

 metamorphic steps of consecutive moults, commencing with the young and finishing 

 with the fully matured bird. 



Further examples of this latter kind are to be seen on the left side of No. 21, an 

 adult male, in which the carpals and coverts 1 and 2 have been completed, as have 

 their respective remiges. Coverts 3 and 4 are equally incomplete as are these remiges. 

 This condition obtains independently and in addition to the renewal of coverts 8-10 as 

 a first definite group. On the left side of No. 23, a young female, we have, besides the 

 same independent final formation of Group I., the incomplete growth of coverts 3 

 and 4, which, though slightly in advance of growth as compared with the other side, is 

 proportionate to that of their equally incomplete remiges ; whilst at this stage, 



VOL. XVI. — PART VIII. No. 5. — May, 1903. 3 h 



