1.50 Div. 1. ^^:RTEBRATE ANIMALS.— AYES. Class 2. 



which we can have no idea, and from the most ancient times has caused to be attri- 

 buted to them, by superstitious persons, a power of announcing future events. It is 

 doubtless upon this faculty that the instinct depends which [periodically] agitates 

 migratory Birds, and impels them to direct their course towards the equator when 

 winter approaches, and pole-ward at the return of spring.* They are not devoid of 

 memory, and even imagination — for they dream ; and every body knows with what 

 facility they may be tamed, taught [in numerous instances] to perform various services, 

 and to retain airs and words. 



DIVISION OF THE CLASS OF BIRDS INTO ORDERS. 



Of all clasps of animals, that of Birds is the most strongly characterized, that in 

 which the species bear the greatest mutual resemblance, and which is separated from 

 all others by the widest interval. 



Their systematic arrangement is based, as in the Mammalia, on the organs of man- 

 ducation or the beak, and on those of prehension, which are again the beak, and more 

 particularly the feet. [The configuration of the sternal apparatus, also, (which we 

 have illustrated by numerous figures,) and the modifications of the digestive and some- 

 times vocal organs, supply highly important characters on which to ground the 

 subdivisions.] 



One is first struck by the character of webbed feet, or those wherein the toes are 

 connected by membranes, that distinguish all swimming Birds. f The backward position 

 of their feet, the elongation of the sternum, the neck, often longer than the legs, to 

 enable them to reach below them, the close, shining jilumage, impervious to water, — 

 altogether concur with the feet to make good navigators of the Palmipedes. 



In other Birds, which have also most frequently some small web to their feet, at 

 least between the two external toes, we observe elevated tarsi ; legs denuded of feathers 

 above the heel-joint; a slender shape; in fine, all the requisites for fording along 

 shallow water, in search of nourishment. Such, in fact, is the regimen of the greater 

 number ; and, although some of them resort exclusively to dry places, they are never- 

 theless termed Shore-birds or Waders. 



Amongst the true land-birds, the GalUnacece have — like our domestic Cock — a hea%y 

 carriage, a short flight, the beak moderate, its ujiper mandible vaulted, the nostrils 

 ])artly covered by a soft and tumid scale, and almost always the edges of the toes 

 indented, with short membranes between the bases of those in front. They subsist 

 chiefly on grain. 



Birds of prey have a crooked beak, with its point sharp and curving downward ; 

 and the nostrils pierced in a membrane that invests its base : their feet [save in the 

 Vulture group] are armed with stout talons. They live on flesh, and [the Vultures 



♦ It il ctTlnin, however, Ihnl llic rspid ciiliirtirmcnt of the scxunl 

 orgniih is lh<- iiiiiiiiiliHH' Hliiiiulnnt to iMiuriitiun in the spiiiig ; while 

 dvcliuc of tcinpcrnture, most Ki'm.Tully, is tlie ciirtctly prtiiisposiliu 

 •cent in the nutiinin : tliis is niJiiiifcst in the case of mii;nitory Birds 

 kept in confinement. The instiin. :cs of the Swift, iinil tidiilt Cuckoo, 

 retiring noutiiviard «t the hottest scnson of llie year, are more difficult 

 of cvplanation, and indicate uome ulterior agency not hitherto divined ; 

 Ihonyh they do not affect the multitudinous observations, which con- 

 clusively prove the inlluence of decline of temperature. It is less easy 

 lo imagine physical ai^ency that should constantly inijiel mi^jratory 

 an'maU ti» travel in the ri^ht direct! It; anrl the marvel increases 



more the extraordinary fact (familiar to all practical observers) o( 

 Birils of passane, uiile.ss when driven by stress of weather, returninjr. 

 both in summer and winter, to their former place of abode, and this 

 even when reared in confinement, and released immediately previous 

 to their first journey. — Eu. (See note to p. 31.? 



t It is most difficult thus to seneraliic in the class of Birds. For 

 instance, the Gallinules, or Muorficut, — habitual swimmers, — Lave no 

 connecting membrane to the toes ; while the Terns, which are never 

 seen to swim, have their toes completely webbed, Stc, Even the Herons, 

 the Curlews, and numerous other iritdcrtf will sometimes take the 

 water of their own accord, and swim across pools, though their i»truc- 



when we consider the length of route ordinarily traversed, and still ' ture docs not indicate such a habit.— Ed. 



