12 PROF. W. LILLJEBORG ON THE CLASS OF BIRDS. [Jan. 9, 



Order 9. Accipitres, Linne. 



The bill covered with a cere at the base, convex towards the point ; 

 and the point of the upper jaw bent down in the form of a hook. 

 The legs strong, with three anterior toes, which are not united and 

 are, like the hind toe, armed with strong bent claws. The wings 

 large, with the large upper wing-coverts of the first row on the lower 

 arm extending beyond the middle of the cubital quills. Two caro- 

 tides communes. They have a strong power of flying, but run 

 badly*, and do not jump. Doubly monogamous. Altrices. Their 

 food consists generally of vertebrated animals. 



Order 10. Strisores, Cabanis. 



The bill without a cere, hard at the base, without any swollen 

 skin at the nostrils, and of a variable form. Three anterior toes, 

 which are generally united at the base, sometimes there united by 

 a web, and seldom free. The hind toe is at times turned forwards. 

 The claw of the hind toe is smaller than the claw on the middle an- 

 terior toe (Sundevall). The large upper wing-coverts of the first 

 row on the lower arm extend beyond the middle of the cubital quills. 

 Some of them (Caprimulgus, Coracias, Alcedo) have two carotides 

 communes, and some (Cypselus, Trochilus, Merops) have only one. 

 Buceros is unknown as regards its carotides. Some fly remarkably 

 well, others not so well. The legs are short in most of them, and 

 not well adapted for walking. Doubly monogamous. Altrices. 



Note. — A polymorphic group, that shows a tendency as well to- 

 wards the Accipitres and Zygodactyli as towards the Passeres. 



Order 11. Zygodactyli, Vieillot. 



Two anterior and two hind toes, or sometimes two anterior and 

 one hind toef, or one hind toe and three anterior ones, the exterior 

 one of which is turned backwards. The claws compressed. The 

 large upper wing-coverts of the first row on the lower arm, except 

 in the Picidce and Bucconidce, do not extend beyond the middle of 

 the cubital quills. Some have two carotides communes, and others 

 (Picus, Ramphastos, Cacatua) only one. The power of flying not 

 very good. They generally walk badly on the ground ; but a great 

 many of them climb well on the trees, and cling skilfully to the 

 branches. Doubly monogamous. Altrices. 



Order 12. Passeres, Linne; Sundevall. 



Three anterior toes and one hind toe, and the exterior anterior toe 

 generally at the base united with the middle one. The claw of the 

 the hind toe as large as that of the middle anterior toe ; and its long 

 flexor muscle separated from the muscle that bends the claw phalanx 

 of the anterior toes (Sundevall). The large upper wing-coverts of 



* Gt/pogcrwius deviates from this. 



t The thumb or the proper hind toe, wliieh corresponds with the inner hind 

 toe in the others, is in tin's case missing, except in the Trogonidoe. 



