123 TROPICAL NATURE, AND OTHER ESSAYS. 



family named Trocliilidse. They are all small birds, tlie 

 largest known being abont tlie size of a swallow, while 

 the smallest are minute creatures whose bodies are hardly 

 larger than a humble-bee. Their distinguishing features 

 are excessively short legs and feet, very long and pointed 

 wings, a long and slender bill, and a long extensible 

 tubular tongue ; and these characters are found combined 

 in no other birds. The feet are exceedingly small and 

 delicate, often beautifully tufted with down, and so short 

 as to be hardly visible beyond the plumage. The toes 

 are placed as in most birds, three in front and one behind, 

 and have very strong and sharply curved claws ; and the 

 feet serve probably to cling to a perch rather than to 

 give any movement to the body. The wings are long 

 and narrow, but strongly formed ; and the first quill is 

 the longest, a peculiarity found in hardly any other 

 birds but a few of the swifts. The bill varies greatly in 

 length, but is always long, slender, and pointed, the 

 upper mandible being the widest and lapping over the 

 lower at each side, thus affording complete protection to 

 the delicate tongue the perfect action of which is 

 essential to the bird's existence. The humming-bird's 

 tongue is very long, and is capable of being greatly 

 extended beyond the beak and rapidly drawn back, by 

 means of muscles which are attached to the hyoid or 

 tongue-bones, and bend round over the back and top of 

 the head to the very forehead, just as in the wood- 

 peckers. The two blades or laminao, of which the 

 tongues of birds usually seem to be formed, are here 

 greatly lengthened, broadened out, and each rolled up ; 

 so as to form a complete double tube connected down the 

 middle, and with the outer edges in contact but not 



