xii NORTH AMERICAN lURDS. 



liiitclii'd at ii tciiqiui'iilure Dl'iilimil Jd-t" F. (goncnilly liy the iiiculiiitiiui iqioii 



UlCllI 111' lllU llinlllcl'J.l 



Such an- sdiiu' ol' the •'■ .iliircs cdiiiiiion to all the cxistiiiL;- sjierii'is iil' liinls.- 

 ]\laii_v (ilhers uiii^hl hi; I'liuniriati'd, hul only lliusc are 'j,\\vn which contrast 

 with the chai'aelei'istics of the nianunals on the one haml and those of the 

 reptiles on the other. 'I'he interior vertehrates are di -liniiuished liy so 

 many salient charactei's and are so widely separated from the hiiiher that 

 they need not he compared with the ]iresent class. 



Although liirds are of course readily reco,i;iiiza.iile hy the oliserver. and ai'e 

 detinahle al once, cxistiiii;' under jiresent conditions, as wai'Ui-hlooded \'erle- 

 lirates, with the anterior niendiers prinulivcly adai)teil for IliL^ht, — they are 

 sometimes aliorlivc, — and ((i\ered with feathers, such characteristics do not 

 sutlice to enalile us to appreciati' the relations of the class. The character- 

 istics have heen '/wvu nioi-e lully in order to jiernut a comparison lietween 

 the mendiers of the <-lass and those of the mammals and rejitiles. 'i'he class 

 is without (!.\ce]ilion the most homo,L;cneous in the animal kiuL^dom ; and 

 amouu the lixim^' foi'uis less diU'erences are oliservahle than lietween the re]ire- 

 sentati\es of many natural ordei's anions other classes, iliit still ihi' diffei'- 

 ences lietween them and ihi' other existing forms are sullicient, ]ierlia]is, to 

 authorize the disiinction of the yroup as a class, and such rank has always 

 lieen allowed e.\ce]it iu,i;' liv one recent naturalist. 



i'lUt if we furl her compare the characters of ihe class, it heconies evident 

 that those shared in common 'vitli the reptiles are nuich more numerous 

 than those shared wiili the mamm.ds. In this respect the \ iews of natui'al- 

 ists ha\e chan'^cd within receui years. l'"ormerly tlui two cliaracter- 

 isli<'s shared with the mannuals - the (piadrilocular heart and warm lilood 

 — Were dcciueil evidences of the clos(> aHiiMty of the two groups, and 

 they wer(! eonsei|Ucntly coiuhined as a section of the vfrlelirates, under 

 the name of Warm-Mooded W'rt el nates. Hut recently the tendency has 

 liecii, and very jusilv, to consider the lards and reptiles as mciuliers of 

 a coiuiuon ui'oup, separated on the one hand from .he nuinnnals and 

 on the other fmni the liatrachians ; and to this coml'inalion of hii'ds and 

 reptiles has lieen liiven tin; name Snni'd/isii/ii. 



' I)r. t'niii^, ill liN " Kiv 111 Nmtli .Vimii'Mii Ilinls," f;iv(■^ mi iil>f' ;nMl lAlriiili'.l mtirlv nn 

 tlir ,i;riii'i;il . liai:iili li-lii^ lir liieU, .■iii'l nil lliiii iiili'iii;il iiml rMn mil ;iiiatoiii\ , In « hi. li «!■ 

 ivlir (Mil- iviiiliis. .\ |ill|ii rtiy I'l■ll|■(■^^^^ !•'.. ,>>. McHM' ill lllr ".\llll;lls cil'lllc NrW ViilK l.yi'clllll III' 

 Xaliiial lli>liiiy" i.\, IsillO, "I'li llii' ('iii|iiis ai^il '"..nsus nl' liiids," i.s nf iiiiiili sriciililir viiliic, 



- Ciiois mill (li'isl.in K.r iilaiiilliii.il .l.r /,iiii1.i,l.'i. . ISii'<, tlMi piv-. nl ih.- I. .11. .win;; .l.liiiili.iii 

 111' l.ii.ls a-i a I'la-i : 



Aves. Skill iiivii.'.l vvli.illv 111 ill part uilli IValluT-.. .Viil.ai.ir |iair nl' liiii'.-, .'.no cili.l iiiln 

 wiiii.'^, .i;iiii'iiilly il>nl ill lli;;lil ; ■..niiiliiii.'s rii.liiiii'iilaiy. Oiii|iiil with :i sin;;!.' iniiiiyli'. .'aws 

 i'ii."i>.i'il ill liMiiiy slicaili^, wliiili r.iiiii 11 I. ill ; Inwcr jaw .if sc>vir,il rlfiiiriitMiiiil iiili.'iilulr.l lirliiml 

 willi a .li-liii.l ijiiiiiliali' liciiii' iilliii'lii'il to till' skull. Kimi-I « illi ilmililc iiiiri.l.' iiml ilniil'l.' v.'ii- 

 lli. l.>. .\il--|.a.i'S .■iiiiiic.li'il 111 II yrnltrr iir Irss rxtclll with Ilir llUlifs ; llli' sk.'li'tnll llHUv nl' li-s 



|iii.iiiiiatir. |ii,iiiliia;.'iii iiii-.iiii|ilrli'. I'l'lvis uniri'iilly ii|ii'ii. i;i]>r.i.lii.liiiii l.y chjxn, r.Tlili/.'.l 

 williili 111.' 1..h1\ , aii.l lial. Iii'.l c.Mclliiilly, ritlnr liy ili.illialinii iir li\ Milm- liral ; tlii' .sIicIIm ral- 

 laii'iiii'' ami lianl. 



