MOEPHOLOGT OF THE OWLS. 23-5 



nwards. The only other birds that I can recall in wliicli a similar arrangement obtains 

 are Caprhmilgtis and Rhea. 

 Semiplumoi : — 



Somiplumes * occur in the interscapular fork of the pt. spinalis, and compose tlu; 

 branches of the lower Y-shaped portion of this tract. The femoral tract is largely made 

 up of semiplumes. The inner border of the pf. humeralis is bounded by semiplumes, so also 

 is i\io.iit. colli ventralls ; they also cover the axillary patagial fold. If the wing of a frcsbly- 

 killed Owl be raised, a large bare sj)ace will be seen entirely liounded by semiplumes. 

 They run along the recurved limb of the median branch of ventral tract, downwards, or, 

 rather, backwards, from the origin of this to the pt. femoralls, the anterior border of 

 which forms its jiosterior boundary, and hem in the space dorsally through the branches 

 of the luml)£ir fork of the pt. spinalis, finally joining the j)Osterior end of the pt. humeralis. 

 Thus, this portion of the apt. trimc. laterale (p. 231<) is entirely shut off from that 

 lying between the pt. humeralis and pt. spinalis, and that between the inner and 

 median branches of the pt. ventralls and the inner branch of the pit. ventralis and the 

 thigh. 



PlumulcB : — 



Plumulaj or down-feathers are entirely absent on the trunk ; they occur onli/ on the 

 wing, and are distributed as follows : — On the dorsal surface they are absent along the 

 preaxial border of the wing ; behind this they occur singly between the contour-feathers 

 m such a way as to form a quincunx with them (thus — ' • )' ^'^^ down-featlier occupying 

 the centre. Two are found at the l>ase of every major covert, and two at the base of 

 every remex (PI. 27). On the manus there is but one doAvn-feather to each major covert. 

 Their distribution on the under surface of the wing is much as on the upper. 

 Filoplumce : — 



The filoplumes are very slender and not easy to find. One or more occur at the base 

 of every contour-feather on the body. 



Rhamphothcca. — The reniform external nares pierced through the anterior margin of 

 a soft slightly tumid membrane at the base of the beak, resembling the cere of the 

 Accipitres. For convenience' sake this will in future be called the cere. 



Podolheca. — Clothed with feathers save the base of the terminal phalanx, which is 

 covered by 3 scales. 



Claivs. — There are no claws on the wing ; those of the foot not much curved, rounded, 

 the inner border of the middle claw forming a sharp edge, decreasing in size from the 

 base downwards. 



JJropygiwnt napiform. It is not tufted. 



Moulting. — Moulting takes place once a yeai', in July and August. {Gadow.) 



* It must be remembered that Semiplumoc are nothing more than degenerate coutour-feathers, and can always be 

 distinguished from down-feathers in consequence of their position on the body, which is, necessarily, serial with 

 the contour-feathers. Down-feathers arc always placed between contour-feathers when they occur on pterylic. 

 Semiplumes always occur along the margins of pteryla) — if the whole pteryla is not made up of semiplumes — aud 

 indicate a further restriction of a once wider tract. 



32* 



