MORPHOLOGY 0¥ THE OWLS. 253 



Podotheca. — Planta feathered, save the proximal end. The feathers on the posterior 

 border of the acrotarsium directed upwards. Scales oa the toes more distinct than on 

 the acrotarsium. Pectination of the claw of the middle toe very slightly developed. 



IV. The Distribution of the Neossoptiles or Nestling-Down. 



I hoped to liave been enabled to describe tbe nestling-down of Aslo, but after all failed 

 to procure a specimen of this genus. By the kindness, however, of my friend 

 Mr. Meiuertzliagen, a substitute has been provided in a nestling Speotijto cnnicularia, 

 which was one of a clutch of 5 bred in the Mottisfont aviaries this spring (1897). 



There are two kinds of nestliug-dowu to be distinguished : (1) the down-feathers 

 ■which precede the future definitive contour-feathers, and (2) those which precede the 

 future definitive down-feathers. This is a j)oint not to be overlooked, inasmuch as the 

 latter, as I have already shown in the case of Op'tsthocomus (14 a), may, from the 

 greater length and number of the rami, bear the greater share in clothing the young 

 bird. 



Just as in Opistlwcomus, the nestling-plumage of tlie Common Kestrel, Falco tiiiimn- 

 culus, is mainly contributed by the down-feathers belonging to the second kind, the 

 down-tufts preceding the contour-feathers being relatively insignificant in size. 



One might naturally expect to find that this two-fold down-clothing would obtain 

 wlierever coutoiu-- and down-feathers were to be found associated together in the adult. 

 This does not, however, appear to be the case, inasmuch as I find that the nestling-down 

 of the Common Duck, for instance, is entirely composed of the down-feathers of the first 

 order — those preceding the contour-feathers. 



I would now suggest that these two kinds of nestling-down should in future be 

 carefully distinguished when describing the plumage of nestling-birds. The feathers 

 preceding the contour-feathers might be called pre-ioenncB, whilst those preceding the 

 future definitive down-feathers might be called pi^e-plumulte. 



In the nestling of Speotyto the feathers investing the trunk are pre-pennae ; pre-plumulae 

 are absent. As is shown elsewhere, the corresponding plumulse are absent on the trunk 

 of the adult also. The clothing of the wing differs from that of the trunk in that pre- 

 plumulse occur amongst the pre-penna?, hui they are very small and contribute no great 

 part towards the general covering. Whether these last are really pre-plimiulae or the 

 actual definitive down-feathers I am unable to decide. Tlie question can be settled only 

 by the examination of younger specimens, the one under consideration being half-tledged. 



Save the remiges and their dorsal major coverts, and the rectrices, the true contour- 

 featliers of the adult do not seem to be devc-loped till after the first moult. All the 

 nestlings which I have been enabled to examine — ranging up to birds nearly full-grown — 

 have been clothed with a peculiar loose semiplumous covering, sprinkled here and there, 

 in some cases, with typical adult contour-feathers. 



