ME. E. DEGEN ON ECDTSIS. 387 



The moult of these inferior medians, moreover, appears to be more erratic than is 

 the case for the corresponding dorsal row of coverts. Besides this there exists a strong 

 tendency to adhere to the conditions of the first endowment, in which the whole series 

 is provided by a gradual advance of the growth from the elbow- towards the wrist-joint. 

 The young female, No. 14 (see diagram Table V. fig. 7), is a particularly typical case 

 of such a repetition of conditions, and so also is No. 4, a younger female still, as regards 

 its left side only. 



It is not, therefore, until the more matured specimens are consulted that the same 

 plan as the one ascribed to their dorsal companion-coverts will be found to have been 

 resorted to, namely, the moulting of the feathers within the groups in distinctly 

 alternate directions. Even this, their ultimate order of perfect synchronism of 

 movement with their respective remiges and major coverts, is not achieved by any but 

 positively old birds, and that tendency to retardation, as referred to above, prevails for 

 a considerably longer period of the bird's lifetime. The diagrams for the specimens of 

 Table V. figs. 7-10 further supplement the explanation given above for the relative 

 position of the ventral to the dorsal median coverts. 



This conservative tendency is fully borne out by specimen No. 17 (Table V. fig. 8), 

 which, although being entitled in other respects to be put down as an old male, has, 

 nevertheless, only four of these coverts renewed in proportion to the eight cubital 

 remiges on both wings ; these are inner coverts 9 and 10, and the outer coverts 1 and 2. 

 No. 20, too, with the same number of remiges renewed already as No. 17 (the previous 

 specimen), has only two of these coverts in moult. 



This tenacity to adhere to the juvenile conditions of growth is carried far within the 

 grouping arrangement also in No. 11 (Table V. fig. 9), in which it is adhered to in 

 the first group, comprising coverts 8-10, whose numbers instead of being renewed in 

 this, their ultimate numerical order, are being still renewed in inverse order — that 

 is, from 10 to 8, as they would be in a bird of the first season's plumage. On the 

 other hand, this same individual shows for coverts 1, 2, 3, and 4 (inclusive of the carpal 

 covert), which form the members of group 2, ail the conditions followed by a bird of a 

 more advanced stage, by beginning the moult from the carpal joint to the 4th, i. e. from 

 the wrist towards the middle. The old males, Nos. 24 (see also diagr.. Table V. fig. 10) 

 and 25, approach the conditions of perfect synchronous development with their flight- 

 feathers ; and, further, the old male No. 1 equally bears reliable testimony on its left 

 side for inferior median covert 8 being the first to be renewed, together with its 

 corresponding main quill. 



In addition to the remarks made above on the subject of bilateral symmetry, it 

 should be pointed out that not only are cases of asymmetry more numerous when 

 compared with the corresponding two cubital portions of the wing, but also for their 

 hand-portions. Thus, in old males three out of a total of eleven are asymmetrical ; 



VOL. XYi. — FAKT VIII. No. 6. — May, 1903. 3 i 



