LOCOMOTION. 257 



greatly more active than the very small black ant 

 (Ponera contracta, LATREILLE). 



There cannot, however, be a doubt that the wren 

 and the tomtit are more active and restless than 

 the bustard, the ostrich, or even the eagle ; and the 

 activity moreover of such small birds is not, like 

 that of the gnat, confined to an hour or two, but 

 continues almost uninterruptedly during sunlight, 

 sleep being, it would appear, less necessary than it 

 is to larger animals to restore vigour after exertions 

 so long continued. Motion of some kind indeed 

 seems as indispensable to life as food and air ; and 

 even the motions of animals, which may be pri- 

 marily accounted for'by referring to their exertions 

 to procure subsistence, and shelter, and the like, 

 must always, in a secondary point of view, give 

 them beneficial exercise. 



" All living creatures," says Pliny, " have one 

 certaine manner of marching and going, according 

 to their several kinds, unto which tjiey keep, and 

 alter not. Birds only vary their course, whether 

 they go upon the ground or flie in the aire. Some 

 walke their stations, as crows and choughs ; others 

 hop and skip, as sparrows and ousels : some run, as 

 partridges, woodcocks, and snipes; others again 

 cast out their feet before them, staulk and jet as 

 they go, as storks and cranes."* 



There is a British bird, the swift (Cypselus mura- 

 rius, TEMMINCK), which has, at least in name (Apus, 

 BELON ; Hirundo Apus, LINNAEUS), been represented 

 as destitute of feet ; but though its legs are exceed- 

 ingly short, the structure of its feet is admirably 

 adapted to its economy. The shortness of the legs 

 and the great length of the wings render it very 

 difficult, if not impossible, for it to rise from an 

 even surface, and, as if conscious of this inability, 

 it is never seen to light on the ground ; " but," as 



* Holland's Plinie, x., 38. 

 Y2 



