MR. E. DEGEN ON ECDTSIS. 381. 



first batch of Nov. 5, with Nos. 2 and 3, it is noticeable that, of the birds received 

 before the dates of December 11 and 19, which are represented by specimens Nos. 14 

 and 16 respectively, none exhibit any signs of moult having set in for this row of 

 coverts. Nearly all of these represent young birds, and there is good reason for 

 assuming that Nos. 9 and 10 are not fully adult either, as I considered them to be at 

 that time, judging from external appearance alone. It is therefore evident that 

 the renewal of this row amongst younger birds does not set in until about towards the 

 middle of the period of perennial moult. 



The renewal of this series takes place in the same order as that of their respective 

 remiges and upper major coverts, which commences with the innermost and concludes 

 with the 10th or outermost, though differing in regard to chronicism according to age. 



In the youngest birds no lower major covert is renewed until nearly six to eight 

 flight-feathers have been formed. From this retarded appearance every subsequent 

 moult recovers one or two places from the flight- feathers which moult in advance of 

 them, till, finally, in the perfectly adult stage, their renewal synchronizes absolutely 

 with that of the flight- feather with which they are associated. 



The most instructive specimen on the list, representing this culminating phase, is 

 that of the old male No. 1 (see Table IV. fig. 6), which is also one of the earliest for 

 beginning the moult for this series of feathers. Its remiges I. and II., together with 

 their dorsal major coverts, which under all circumstances are the earliest to moult, are 

 simultaneously accompanied in moult by their respective ventral major coverts. 

 Indeed, on its left side, the inferior covert 3 is slightly in advance for making its 

 appearance of the old reraex III., which, having just been shed off, shows no sign yet 

 of the new-growth quill. The same condition obtains for the remiges on the right 

 side of the wing, the inferior coverts 1 and 2 being synchronous with the dorsal ones, 

 which are being renewed also at this stage. 



The adult male No. 25 is similarly characteristic for almost perfect synchronism, 

 though No. 24, an old male too, of Avhich a diagram has been appended (Table IV. 

 fig, 4), represents one of the later stages of transition from the juvenile to the fully 

 adult phase of this row in relation to the flight-feathers. Both these specimens were 

 procured towards the end of the moulting-season, as their numbering shows, and 

 accordingly were in a much more advanced condition of the moult. 



The remaining specimens, Nos. 17-20, represent every conceivable transitory phase 

 of retardation from their remiges by a steady progression for each moult of one ventral 

 major covert, from their original arrear of 8 (well instanced by specimen No. 18, 

 see diagr. Table IV. fig. 5) down to the case of absolutely simultaneous movement so 

 characteristic of adult birds, as explained above ; this is continued through every 

 subsequent moult of the bird's life. 



The diagrams on Table IV. (major coverts) for specimens Nos. 18 (fig. 5), 14 (fig. 2), 

 19 (fig. 3), 1 (fig. 6), and 24 (fig. 4) illustrate some of these transitory stages. 



3 h2 



