﻿126 ON THE CLASSIFICATION OF BIRDS. 



come the wings of the latter : bearing in mind this 

 analogy, we find that the lemurs (Lemuridce), opposums 

 (Didelphidce), and kangaroos (Marsnpidce)* , are among 

 the largest footed quadrupeds. While the water rails 

 (Rallidce) , the greatfoots (Cracidce)\> the honey suckers 

 (Meliphagidce), and the large-legged thrushes (Oa- 

 teropince), among birds, have the largest feet, with the 

 largest claws, in the circles which respectively contain 

 them : they are all, in short, so many instances of the 

 Rasorial type. Size and strength of foot must not, 

 however, be confounded with length, for those birds 

 which have the longest, have generally the most slender 

 legs ; the whole of the typical Grallatores, or waders, 

 butcmore especially the genera, Himantopus, Avosetta, 

 Mycteria, and Tachydromus. The flamingos (Fhceni- 

 copterus) among the Anatidce ; the serpent-eater {Gypo- 

 geranus), in the rapacious order, and the larks in the 

 circle of the FringilUdce, are analogous types, and show 

 that unusual length and slenderness of leg, where it 

 exists, is generally prevalent in the Grallatorial types. 

 The shortest feet, as just remarked, are almost always 

 found in the aquatic type, whether belonging to the 

 class of quadrupeds or to that of birds. The seals 

 and walruses, thus representing the pelicans, ducks, 

 awks, and divers, in the Natatorial order, and these 

 find their representatives among the perching groups, 

 in the night-jars {Caprimulgidce) , swifts (Hirundinidce) , 

 flycatchers (Muscicapidce), short-legged thrushes (Bra- 

 chypodince), and numerous other groups. Moderate 

 feet (that is, when the tarsus is only slightly longer than 

 the hind toe) is the average structure in the rapacious 

 and perching orders, but the claws of the former, like the 

 feline order of quadrupeds, are retractile, while the 

 latter agree with the feet of the quadmmana in having 

 superior powers of grasping, or of prehension. Thus we 

 perceive that the relative size of the feet, throughout 

 the class of birds, is regulated by fixed laws, and that 



* See Classification of Quadrupeds, pp. 82. 106. 532. 

 f This family includes Menura and Megapodius. 



