TISSUE DIFFERENTIATION AND RATE OF GROWTH. 



on the seventh day. A single loop, probably functional, is 

 plain on the eighth (Fig. 4), but the organ does not appear to 

 be mature even on the lenih. 



All organs and ii ne- except the nephridia appear to be func- 

 tional on the eighth day. They have al-o reached apparent 

 maturity by the tenth day. -onie before. The data an- not as 

 romp!' mid be u i-hed but they certainly are very indicative 



ot a iorrelation between the maximum rate of growth and the 

 period ol di-tinct differentiation. Thi- i- e-p.-cially true \\lu-n 



\\e con-ider the fact that the tenth regenerated -cement is the one 

 for uhi.h these data are rer.,rded and that its maximum -peed 

 rou th fall- on the ninth d.iy. 



I KPERIMEN1 II. A\ IMMAHKI \\t\i.\i.. . 1 ;;/'/ ystonni 



T\M-M| i . 



M> '.' -</\. 



'iid in. ii I'L ton, Ind., probably in the ni<Jn of 



Jaim.in -" idition at thi- laboratoix 



on lebtii.:i\ i. I'hev \\ete kepi in -mall lot- under similar 

 condition i \ariatioii in uater. until it ua- found that the\ 



did ver> \\ell ir. i.iji er \\hich ii ua- u-eil regul.irly. 



I p in the time 'l haii hin^, ihe main ellun- \r control \\ere in 

 the line !" char. :i mv belo\\ j, i ( ., 



an<l a\ i -id. mi ! d:n. -nnli^ht. 



On Febl uai \ -adpolc- . -lei led from a ijtiile 



uniform loi and |>la.e.| -in^K in berrv di-he- \\ilh about 50 . 

 of i.ip wat( : ( Mi the these individual- were about t \\ o 



da\- from th noiu- more than Imir nor le-- than one. The 



di-he- \\eie jiailK iporation. \\alei \\a- 



chan^ed and the di-he- \\a-hcd I \\ o or three time- per ue.k. 



I f( -ll \\aler ua- frei;i|elltl\ added betUeell tillK'- if C'\ a] >of, 1 1 ioil 



:H'<| excessive. Ihe temperature record ua- taken twice 



dail\ . \o eflforts to feed wen : ul until l-Vbniar\ 20. 



\\'ithin a few da\ - main \\ere feeding readily on live I.innimlrilns 

 which ua- u-ed i oininiioii-l\ to the end of the experiment. 



l'.\ Man Ii ll several death- had occurred but the lai 

 number of tadjiole . -d to be \\ell .idju-ie I. seventy of tin- 



be tier -pecimcn- averaging about J > mm. in length \\ere n-iaim d, 



