VI. 



niijillliitrtl 

 ii|>l)iUiitus 

 , tlu' iintf- 

 f the lirst 



ses of the 

 atlu'r tliiiii 

 •ilsiiri'foii- 

 ircli, \vlii<^h 

 bacUwiirtls 

 boiu's. A 



piMllliUll'Ut 



It coiulitioti 

 liiiiclius. 

 is UDiic (»U 



icteis which 

 sfDriniitioii : 

 farpiis lunl 

 lauchiii' ilis- 

 niouth ; (0) 

 transverse ; 

 [)horie of the 

 rreiice. But 

 served in all 

 )r the other 

 ■ si)eeies has 

 ilari;.\ in the 

 le earlier pe- 

 a of his Knt 

 the vertebral 

 in the nsnal 



rodnetion to 

 evident that 

 of variation, 

 n the expel i 

 i greatly has- 

 t,\vhat wonld 



of a ehangf 

 I'ssion of the 

 Hinliarities of 



cnnnierated, 

 IS speeies as 

 ;ogni/>e. For 

 lies below. 



I 



TlIK IIATUACMIIA (»l' N'OlM'll AMi:UU'A. 



49 



Tlie expeiinu'niH of lloi;^, above albided t*., are as ftdlows, as t,Mven 

 l»y him in the Annals and Ma;;azineof Natnral History. 



llo placed a nnnd)er of inii>rej;nated ova of fro;,'s in vessels arran;;ed at 

 re;;ular distances from th(! li;,Hit in a cave. The lessenin;,' degi'ees of 

 lij^ht were of conrsi' acurompanied by a (!orres|»ondin};' bnt much less 

 rapid decline in temperatnre. The rcsullin;;' ellcclson the metamorpho- 

 sis may he tabnlat»'d as follows: 



j^Ii'^ii. I'iiliri'iilii'il 



111" 



Kii 



:i 11 K!:i; 



■JO l.iiiva In i> ' 



■j."i ■ : li;ii \ ;t licr 



;ii • . - ' 



1 111 I,iivj viTv liii';;i' !,:itv;i 1 n-'- 



'11 Mi'l.iiniiiiiliiisi.i uoiii MrlMiiiiir|p|iii.-(i.i I'oiii 



X 11 



■IX 



Ill :ii 



.w 



51 J 



I0U« K'AK 



I.iiiMi IriM' I.iii va I'lnv 



l.ai va lai'}!i< Larva Miiiall. 



Mrtiiin(ir|ili().si« fiiiii * 



|il(|i'. 



Mrtaiiiiii pliiLsin ciiiM 



|.l...r. 



Other experiments, whicli will not be (pioted now, aic ('(pially (ton- 

 elusive as tot lie effects of iinlit and heat on their process. The dis- 

 tinction between iiiatiirity, or adult aj;v, and complete devel()pinent 

 must be borne in mind. The former (Mtiiditioii is attaiiu'd when the ova 

 an; fitted for imprej^iiation and the spermatozodids are capable of accom- 

 plishing; that result. Development may or may not advance much 

 beyond this perioil. .Vs one or more periolsin the life of every species 

 is characterized by a i^reater rapidity of develoinnent (or metaiiKM'pho- 

 sis) than the remainder, so in proportion to the approximation of such 

 a period to tlm ei>ocli of maturity or reproduction is the olfspriny liable 

 to variation. 



The j^reat dilVerence l)etween the dilfereiit speeies and between indi- 

 viduals of the same species in this res|(t'ct, may bi> illustrated by the 

 followinn' comparison between the siz,' of the ani inuls at the time of 

 losiiin' the biaiicliia-, so far as known, and that to which they nlti- 

 matelv attained : 



Sprrii'H. 



Aiiililyiliiiiia.iill'rrsDiiianm' 

 Aiiililystuiiii |iiiiirtatiiiii .. . 

 A iiiM.s stiiina i'iins|iri.Hiiiii . . 



Aiiiltlysli'iiia opandii 



Oliiiiiilriitiis li'\aiiuH 



('Iiiiiiili'iitiis nili'msloiniis . . 

 Aiiihh .sloiiia talpiiiilcHiii . .. 

 CliiinilKitus paruticiis 



Ainljlysloiiia tiiji iiuiiii 



('Iiiiiiili'iitim li>iii'l>i'iiHiiH 



• I'll Imp** liMi lai ;;(■ 



i!>.")i— liuU ;u — 1 



t Nut siiiallrsl. 



