244 STRUCTURE AND CLASSIFICATION OF BIRDS 



together the two groups of birds, likenesses which might 

 fairly be put down to similarity of habit. These superficial 

 resemblances are, however, enforced by more deep-lying 

 structural similarities. MITCHELL has found that of the 

 various groups which may be supposed reasonably to be 

 allied to the Caprimulgi the owls come nearest to them in 

 the primitive character of the gut, while the caeca, swollen 

 at the ends, are alike in both. The owls too are nearly the 

 only other Coraciiform birds besides the Caprimulgi which 

 have well-developed basipterygoid processes. The trogons 

 it is true, possess them, but then they differ in many other 

 important particulars. 



STRIGES 



Definition. Oil gland nude. 1 Aquincubital. Both, carotids present. 

 Caeca "well developed, ending in a dilatation. Skull desmognn- 

 thous and holorhinal, with basipterygoid processes. No ambient, 

 semitendinosus, accessory fenioro-caudal, biceps slip, or expansor 

 secundariorum. 



The owls, formerly associated with the Accipitres ant" 1 

 termed 'Accipitres nocturnse,' or ' Nyctharp ages,' are now 

 generally placed by themselves away from the haw r ks and 

 in the neighbourhood of some of the birds comprised under 

 the term ' picarian.' The group itself is characterised by 

 a great uniformity of structure, and by the possession, so to 

 speak, of so many negative characters. The resemblances 

 to the hawks are really only in habits and in beak and claw. 

 These, however, will be dealt with more fully later. 



The owls comprise a considerable number of genera, of 

 which Strix stands rather apart from the rest, having a^ 

 near neighbours the Eastern Pliotodilus 2 and the Madagas- 

 car Helivdilu** 



curious coincidence that the term ' morepork ' is applied to Podargus in Australia, 

 and in New Zealand to an owl, Spilocjlaux Novte-Zclandice (fide NEWTON, Diet, 

 of Birds, sub voce ' Morepork '). 



1 Except Strix and Asio otus. 



- BEDDARD, ' On Photodilm badiits,' Ibis, 1890, p. 293. 



3 MiLNE-Ei>WAiu>s, ' Observations sur les Affinites Zoologiques,' etc., Nonv. 

 Arch. MUK. (2), i. 1878, and in Hist. Nat. de Madagascar. See also B. B. SHARPE, 

 ' A Note on Heliodilus,' P. Z. S. 1879, p. 175. 



