Classification of Birds. 83 



powers of flight, evidently forms the fissirostral type of the Milvine 

 circle, thus bringing it into immediate contact with the common 

 kite of Europe, which we think he very properly excludes from this 

 division, and places among the buzzards as its fissirostral form. 

 The fifth form of Cymindis he thinks it is not improbable may be 

 Vieillot's genus Cirecetus, but we know too little of this group to give 

 an opinion as to the correctness of the supposition. The last division 

 is that of the Buzzards, which, by some of its members, leads back 

 again to the typical Falcons. This group, as he observes, might 

 with more propriety have been called Harriers, as it is the genus 

 Circus which exhibits the fissirostral type of the whole family in 

 the greatest perfection. The subtypical form he considers to be re- 

 presented by Buleo lagopus, in which subgenus he also leaves the 

 common buzzard and other similar forms. In regard to the genus 

 Pernis (honey-buzzard), had the author enjoyed the opportunity of 

 examining the specimens now before us, he would, we think, have 

 found little hesitation in pronouncing it to be the tenuirostral type 

 of the division, as it exhibits the characters of a weak and slender 

 bill, with feet and claws less raptorial in structure than any of its 

 congeners. The common kite, Milvus vulgaris, Temm. as we have 

 previously observed, is considered the fissirostral form of the divi- 

 sion. The fifth or rasorial type is not indicated by Mr Swainson; 

 may it not be represented by the Falco cristatellus, Temm. the Spi- 

 zaetus cristatellus of Jardine and Selby ? 



From the Falconidas, he proceeds to trace the natural series of 

 the Strigidse or owls, confining his exposition to the primary divi- 

 sions and genera only. The passage from the Falconidae is well 

 marked in the genus Circus, where we perceive the first indications 

 of that peculiar ruff of tiled feathers, which surrounds the head, and 

 is seen in its highest developement in the Striginae or typical owls. 

 The formation of the ear, the eye, and facial disk, being the pe- 

 culiar distinctions of this family, he naturally forms his primary 

 groups upon the greater or less developement of these organs. The 

 first, or typical group is therefore, that in which the facial disk is 

 very large and perfect, with large ears, and in general an ample 

 operculum. The second or subtypical, with a large facial disk, 

 but small or moderate sized ears, the head furnished with egrets. 

 The third or aberrant group with the circle of the ear small and des- 

 titute of an operculum, the facial disk imperfect or obsolete, and the 

 head without egrets. This group is as usual divisible into three, each 

 of which possesses its distinguishing characters. The first group is 

 typically represented by the common white or barn owl of this 



