MR. E. DEGEN ON ECDTSIS, 399 



the lateral rows, both internal and external ones — to which latter the pterylse laterales 

 belong, — do not take up the change until considerably later, viz. the stage of renewal 

 of primary remex VIII. 



The centre of moult from the other, namely, that of the "inguinal" or gastric 

 portion — which is a continuation of the pectoral one, consisting of three or four rows 

 of feathers only, — begins also synchronously with that of remex I., or directly after. 

 The progress of renewal of the feathers of this portion is much slower, though slightly 

 faster in the case of the innermost rows than the lateral ones. This condition points 

 to the fact that the inner rows are really equivalent to the median ones of an 

 undivided tract. 



The third centre of feather-renewal for this tract is at the point of bifurcation for 

 the two pectoral rami on the lower throat. Contrary to the mode of moulting, in an 

 antero-posterior direction, of these latter, the moult of this portion proceeds in a forward 

 direction only, until it finally reaches the mentum. It is not till much later on in the 

 season of general moult that it sets in here ; but when it does, it happens in a vigorous 

 manner, which is about the time of remiges VI. and VII. for the central rows. These 

 are followed immediately by the outer rows, which complete their moult at the time 

 of renewal of cubital remex V., the last of the flight-feathers to moult. 



The renewal of the feathers of this tract in the order in which it has been described 

 here is that of the older individuals. In younger birds this order is not so clearly 

 defined. 



The Femoral or Lumbar Tracts (Pterylse femorales sen lumbales). 



These are composed of two rows, consisting of nine or ten soft and elongated contour- 

 feathers each. They are renewed in alternate rotation — that is, by beginning in the 

 superior row with the feather which is situated nearest the apterium sjjinale, to be 

 followed by that of the inferior row next to it, and from whence the feathers are 

 renewed in tolerably regular sequence in backward direction. Though the feathers of 

 this double tract are only few, their renewal, which begins with the earliest phases 

 of the flight-feathers, is not completed till about that of remex VIII. 



The Crural or Tibial Tracts (Pterylee crurales). 



Both portions of these tracts, which clothe the tibia — an inner and an outer one — and 

 which are separated in their upper or femoral portion by an apterium, merging with 

 each other below the knee, moult simultaneously. The moult begins early and 

 synchronously with the centre of moult of the other tracts, from above below, and 

 finishes on the tarsal joints. The time of completion corresponds with the last stages 

 of flight-feather renewal. This is somewhat remarkable for a tract which consists of so 

 few feathers, seeing that their renewal begins at a comparatively early period of the 

 perennial moult and finishes so very late. 



