MAMMALS 



actively, and their hitherto 

 fbod-eaaab. g*ntlv tutored by the readily 

 more or ( rapidly *an|uire what 

 hapfHlv termed a 'gaMric education,' 

 iea .Mk. more MlMaaOal **f-Um. 



(*r.m ../ .V..-..W/* -Thoogn the .lurk mole ami 

 the rVhidna Uv -w, and from lh. i.iu- -I lh-ir 

 C-fiiuU du.i. have hen termed OmilhudelphU, 

 their aAnitie. are rather with reptile. than *nl, 

 ' i and bird* repnwot divergent 

 nMnofl 



hia. the theorie* a* lo the 

 origin of msmmatr are mainly concerned with the 

 robhililini in favour of a reptilian or of an am 

 i4.il.Un aneeatry. ! Mpport of the latter it ha- 

 ham nrged that mammal* ami amphibia bav- t.. 

 kail raodylaa. while hird* ami replile* liave one: 

 thai the quadrate U *mal! in the amphibians and 

 mail*, large in Saaropaida: that wime other 

 part* of the mammalian .kelcUwi (*uch a the 

 pelvi.) tmggmt aftaitMs with amphibian, rattier 

 than Kaurot-tda ; and even that the asapUMaM MI 

 their varied rrpmdactive experiment, an a* lik.-lv 

 aa reptile* to have originated the charm. 

 ^^.^..l..n parturition. On the other hand, the 

 or, prohabililie* are in favour of the reptilian 

 i of mammal*, for UM reptile* are in general 

 raUatiod more evolved. Among the mimer- 

 00* extinct Saurian* UM Thoriomorpha distinctly 



UM bug* partially egineiiiiiig "um 

 noUrme* mm nun h lik-i thai --i 

 than that of amphibian, (which -vlnl.it- 

 rmenlaiioai. while ii i- not without mi.-i.--t 

 that two lizard., ahow aa in. i|.i.-nt fonn of yolk 

 A com prom i**e between tli- rival 

 MB proptjaed by St Gemue Mivart, 

 a dual origin of mammal*, deiiiing 

 from Aii.>milnt or allied reptilian 

 type*. UM Marttupial. fiom a .li-tmct and earlier 

 unrre, parba| ani|>hibuui. Another conipnnniNe, 

 eqoally pnihlnnaMcal, would derive mammalx 

 from a primitive *tork of Angered fiundiu|HfU, 

 the common ajitatoni of amptiihian* and teptil 

 Om UM whole, however, the llance of proUbiliii.^ 

 aawm) in favour of the origin of mammal. fi.>tn 

 extinct Saariaaa. *ch aa UMW uhi-h < ..)- lia 



itml 



m|.| 



o/ Mammal*. Deeper than thr j.,..i. 

 of <iennininj( whether wainiiiaN luul lli.-ir 

 in from aMphibiaiM or repUlen b) thai hi-li 

 faM|ireaini. mally n,nlril.nt.-.| 



la their rte. That tin. mu.l have liern >., 

 irradaal hoth the fi-il form* ami the irradf* whirli 

 (Mill peri*l pbuhlr h... and it i- iin|>rlnt t<i 

 mUW what b iilid a gWMral troth in reuanl to 

 mtiaUo*. that many of UM rbaraetorinUe frutum. 

 f mmml are not > morh nrw ai-.,iusiti,,n. , 

 and elaboration* of what i old. 

 to lu- 



who 



Kaarian*. wh aa tho hi.-h i -.|- 

 I a* Theriomorpba. A few nologi.i*. 

 maintain UM reptilian ancwtry of mammal*. 

 repua Cetacean* a* a very primitive oni- 

 dwive UMM from tb- :-r>gan rt-ptil 



bolth^vMwhaalMMiraenv,.) . it h virtually fatal 



Fot Hlod 



I ' ' ^*. 

 I' I 



U> MM* tvpe an are exhiltited by MmiolriMiic and 

 ml. and from ihe upwards to the climax 

 in man : or the Krndual 

 growth <>f Anllerx (q.v.) 

 from MiiM-i-tn- tiiii on- 

 ward*. a hi-tory nipi<llv 

 n-capitulated in the life 

 of modern atagR. Imt 

 after rraliMng the Knulunl 

 tlf\i-lopiiifiit of t \IM-X anil 

 >trurtur, and appnx-int 

 ini; tin- inllni-inTof niitiiral 

 M-livtion in ili-tfiuiininn PUohlppoa. 

 .li-lnl.iiiioii. ill -hniin:.i 

 nit; ninnt-. in foMrrintf 

 -Mitiiitwii anil <ttreiif.'th. 

 Hiul in jn-tifvinj; l>ij; Pnorfi 

 brainK, many HttarmlMi Hlpparion. 

 xtill find th- pro). Inn of 

 lli- -Miliiliiin ol iiiiimiiinls 

 iniiiiiiplclely wilvwl. It 

 - iiivvKMiry to follow 

 tin- ^-liixil of l-iimatrk in 



The all important mammary gland. eeni 

 twt madiftnatiaaw of the nehamm* vlaiifl. d 

 over UM akin ; the plac-nt . -....,,.. 



UM allMtofe. 

 UM 



UM llhula 



wbi.Vally 



ami 







-re.. ialmvl\ . 

 tm\*\ in reptifa*- and ampliibiaii. N. t.. 

 ample <rvW*a<* of the t cry gradual evolution of 

 * ITM awl 4rwtaraa wrUMaa the long 

 1*CmMMrt UM BOOM Eohippo*. a five 



JIM I. U.rw u-d wunlata. 



ia*a> UM .kalU of 



almat the N|M of a 

 (q.v. ; nee aim Poor); 

 frnm tbr urn all canto 

 (me of the early giant* 



ot u-e and ellort. 

 and tli- inlliiein-e of a 

 changeful env iriinnient on 

 the j- growth 'of 



the organism in definite 

 diiei-tions. l-'iiitliennore, 

 an account of the evolu- 

 tion of mamnmli* has to 

 take account of one of EOCKNE, 

 the moM piMiiiiiieni char- Op.lii|>|ni. 

 a. -ten-til -. the maternal 

 acrilice expniwed in the 

 pla.--ntal union, in the 

 prolonged gmtalion (em- Fig.2. Fore and Hind Feet 



-1 iiiiin\ \eursago of the Hoi 8.- and iU ex- 

 by KoU-it Chambers), MM! tinct Ancestors, 

 in the lacteal nutrition 



after birth, a nactilice which must have IM-CII OTIP 

 of the moht iin]Hii taut factorx in the progress of 

 mammal- Alter a while the inniiinialian mater- 

 nity iperhapif pathological at first and always 

 e\|'ii-i\ei iiiii-t have 

 p. ii. I or jiistili.il itself; 

 hut its recognition ax 

 a Hiiluinlination of self. 

 M to s|M-.-ie- 

 maintaining, of nntiitive 

 l niggle to repriKlnclive 

 a neceawiy 



Cfirreeliie to the pleva- 



lent iln-ory which tends 

 to -nipliasise too exclu 

 nively the conilK-lilive 

 . I niggle for individual 



, . , -. . , 

 hilrllfi 



(ienrral /,ife.1 

 the mnmmalian 

 from the ' frog-wilted ' 

 diii-km-il- to the highest 

 of tin* Primal."., there is 

 a gnulual increiUM' in F ' .-8mll and Cant, of 

 complex it r of l.n.inn Brainnof Eocene JlammaU: 

 I.M. km-, of witH. * *U*rt j 



111- lelniilkllbly d.H-ile 



int.- Ii- dog, D', IHmiSemtmlnbui7' 



the el.-v. mi-*, of the (After Man*.) 



highlv evolved eleiihant, 



.-unity of the mx-ial beavers, and the 

 humatinnv.' of the higher ape* are crowning illux- 

 trationn which t-pcome all the more remaiknlih* 

 when we recall the minute brain* of early inammals. 

 A (-.mtra-it lietween thone type* whicd excel and 

 thone which lag behind will also illustrate Spencer's 



and 



