476 Mr. N. A. Vigors on the Natural Affinities 



Avhy the Dentirostres should be characterized by the raptorial 

 peculiarity, the mandibulary notch ; why some families of the 

 tribe, even down to the smallest Pari*, should have a tendency 

 to attack and prey upon the weaker animals ; and why, from 

 their conformity in such habits, the Laniadce should have been 

 so frequently confounded with the groups of the Raplores. They 

 demonstrate the cause why such birds as the Musophaga and 

 Corythaix, so nearly and evidently allied to the Gallinaceous fa- 

 milies, should be found among the Scansorial; and why the 

 Scansores, to make a selection from many characters which 

 they possess in common, should be distinguished by the short 

 wings and heavy flight that characterize the Rasores. They 

 explain the identity that exists between the typical families of 

 the Tenuirostres and the Grallatores in the suctorial manner of 

 obtaining their food, and the cause why both should be distin- 

 guished by a corresponding length and slenderness of bill. The 

 same considerations of analogy illustrate the general tendency 

 which the families of the Fissirost7'es exhibit to resort to the neigh- 

 bourhood of waters ; why their nests should be so frequently con- 

 structed in their vicinity ; why the Hirundo should pursue its prey 

 along their surface, and the Halcyon seek its food from their 

 depths. They explain, on the other hand, why the wide gape and 

 short tongue of the Fissirostral families should be observable in 

 the PelicanidcE, and the consequent conformity that exists between 

 the two groups in their mode of gulping down their prey ; why the 

 Terns should be commonly denominated Sea-swallows ; and why 

 the variation in the form of the tail among the Perching birds 

 which feed upon the wing, should be equally discernible among 

 the JV^r^a^om// families; the Phaeton and Tachypetes exhibiting 



* Ils(les Mesanges) senourissentd'insectes, les petits oiseaux inaladifs devient 



aussi leur proie, elles les achevent en leur ouvrant la crane. — Temm. Man. d'Ornith. 

 p. 28G. 



the 



