Alligators & Crocodiles pdf epub mobi txt 电子书 下载 2026

， I I I l， ~ I *~ I; ， ~ R t) I (~ I) I I， I ~<br > CI~，()(]OIMLIAN，.; ~，，~. ，.~ .，.，.，.，d~.-v p.l..， :..]. n.p ~. ~l，，， I.，~e of tl，e<br > Of Giants and Dragons ..，~，，e e，，able croc.odilians u~ dose off the wi，~dpipe， a，，d<br > thus Io open Ihe month under waver when they seize their<br >TI. ~.roc~clilian~ mt memlwrs ~1 .u order ~d repHh s prey. They have a partition sep~ ali~ the chest from the<br >.，m~.hnu ，d I1. :tilit~au>rs. tl. ~lmria]. m~d the true erm o- rest of the body cavity， rather like the diaphragm of<br >di5.~. The :m I1 1;，~1 Mn-vi，，m sofl}le，ffyc:d ~reupof rulin~ mammals， This partition can be moved by means of a<br >~cplllcs . he alchosam s Amm1~ Owiv exiinc! relalives， lhe muscle， so thai crocodiliaes can breathe mere ef]]eiently<br >bp~bl， town are Ih( mi~hh dim~sams， All descended frmn thal~ ether reptiles.<br >cCmnnm~ ;~ neestm s IIw theeodonts， wl i ich tlomished durin~~ The crocodilian heart， too， is closer to that of a mammal<br >th~ e~u-I~ "lvia~si( period. 225 million years a~~o. The fossil than to those of oth er reptiles. ~iving them a more effieien!<br >[，.q/)rd ~11o ~ ， I}IM ii}l)derll croeodi]iauts have ehan~ed very circulatory syslem. In most reptiles the heart has three<br >]lille sim ~ Iht!~ lirsl appeared， about 160 million years a~e. chambers. Oxygenated blood from the hmgs and oxygen-<br > III |lit nid~q el an mlcxplained increase in lhe mlmbers of exhausted blood fi om the muscles and internal organs<br >]mu~ n.plih s. Vl.，n that stlr~Ce died down about sixty-five arrives in separate auricles， but is then mixed in a common<br >millit.~ w.m-s a~.o. al the end of the Cretaceous period， and ventricle， The result is that some of the blood being pumped<br >II. rcsl ~t Ihe areho~ams disapl>eared - an equally unex- out into the ~eneral circulation is oxygen-deficient， not<br >pl，su，，，~ ，，v~m! - urns| ot ~l~(~ croeodilians survived. Tl)ey are having passed throqg]， the lungs to l)e recharged. In the<br >t1.， ]ur~，~st livimz reptiles m the world， fearsome and widely heart era croeodilian， the ventricle is divided into two parts<br >fi~ared by a partition， so that ~te-oxy~cenated blood goes only to the<br > COl.D-BLOODED IIORROR lungs and only fleshly oxygemtted blood passes into the<br > eireulation. ，<br >Th，.ve w sm.ethint" aboul the combination of great size and These t~atures make erocodilians especially interesting to<br >cold blood thai i.spires horror in humans， Elephants or biologists. As the only IMng relatives of the :treat dinosaurs，<br > ~zovillas ~t，* hu"e.ev Iml lhey are mammals like ourselves， they provide a clue to the adaptations which may have made<br > inte]ti~. n! with d ]5mi]~ liD. Even lions and tigers are less the dinosaurs so successful tbr such a long period in the<br > ;(~csoll~t- atlcl p~q stq ~lllOvl Ivy Kenerations of hunters， all anilnal history of the earth.<br > l)m the sick ，，~ devau~ ed sh er well clear of mankind. We DRAGONS FROM FAR AWAY<br > t，v~，dil whale， wilh tn ，*al intelliKenee， and there are many<br > ~1，，~ ~es ~d their ~clJ|]c belmvieur， l~，ut crocodilians have no When the first explorers returned fl om Egypt to Greece and<br > I，.a~ m，，I ，.~~.ep， it their parental be|mviour they are by no Rome， they brought back stories of these powerful pre-<br > m~ am， ~m~(le "l he~ are pvedators， of relatively limited daters， Although their reports were t~ctual， they mus~ have<br > mlclli~ n， ， cmd when they see a meal， they take it， I)een hard to believe， anad legends inevitably grew up<br > wh~gh.-r it I，a~ Ibur h Ks m" two. The dread in which they are around them. It cammt have been long betbre these stories<br > h(，hl I)~ mr)，，t oil].( hlllllall Yaet has hastened several Sl)ecies stirred recollections of ancient accounts of other great<br > ，cr，，，ard， px~mct，o，， Fern has mtlt ushed many a spear， and reptiles， sprung not from travellers tales but fi om the<br > dl]~，.~ m~mv ~ .a]hq ~t~ its mark， ilnaginalion t)J story-tellers， or even fl Olll sollle distant<br > ANGIENTOR MODERN? tblk-u|emory of days when erocodilians still tlourished in<br > F， urope and North America- and dragons were thus reborn.<br > Thr.， .，.，， h.~ ;tm .q.v. but cr*}， odilians arc t]ol primitive in Long betbre the (h eeks and Romans， the Egyptians had<br > ，I，~ l， ~m I hci~ bre;tlhiu~g al)par:flt~s is ].ighly de- first-hand knowledge el crocodiles， fi em the cradle of their<br > . . i~(li/~d. The .，)strils m， phte， d al the very civilisation along the banks of the Nile. They regarded them<br > . th.d I1.. :twilnal can I;.t athc whcll Ihe i csl with awe， and soon inehtded a crocodile， Sebek， among<br > d，，m J，，~ ，I ，~ xil，d aid h) ~.;um).fl;，~，c when il is their go(Is. Its eml>odiment on ear/h was a series (1~ sacred<br >