476 Mr. N. A. Vicors on the Natural Affinities 
why 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 Laniadæ should have been 
so frequently confounded with the groups of the Raptores. They 
demonstrate the cause why such birds as the Musophaga and 
Corythaiz, 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 Fissirostres 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 Pelicanide, 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 Natatorial families ; the Phaeton and Tachypetes exhibiting 
* [ls(les Mesanges) se nourissent d’insectes, les petits oiseaux maladifs devient 
aussi leur proie, elles les achévent en leur ouvrant la cráne.— Temm. Man. d'Ornith. 
p. 286. 
the 
