IL C. PUNNRTT AND THK LATK P. (i. BaILKV 7 



between the pnrentM (of. Tuhh* V, p. 25, and Fig. 4). Two Iitu»rH were 

 bnxi fn)in thiH pjiir g^^'^^K * ^ ^'a Hninmls in nil. Th<* aviTiigf si/.f nf 

 tht»8f wiu* (iJHtinctly U'hh than that «»f thr |Nin'n(«, hnt, although th** 

 variability wiiMConHitlorahh', nothing was pnMluc<*<l apiiroiu'hing th<* Nniall 

 Hizv of the grandfather. Possihly this niay ho dm- nu'icly to th«- small 

 ninnl)er of F^ animals roariMl. 



From tho othor Flemish doe (0 208) the numhors an- grcator. Th<* 

 ft>ur /*, animals wore closely intornjodiatv in size hctAvccn the jwinuts 

 (cf. Table V, j). 25, and Fig. 5). From these two /', pairs :U) /aotfspring 

 were n»Ared to maturity. The results are clo.sely comfwirable with those 

 nbUiininl from the otht^r Flemish -Polish mating. There is considerable 

 variability in Fo though very few individuals reach<'d the F^ size and 

 only one exceeded it, and that but slightly. Xo individual shews any 

 approach to the large size of the Flemish. 8f>m<' shewed a fairly close 

 approjich to the small size of the I'olish grandfather, and it seems not 

 unlikely that with larger nutnbers animals of this extreme small size 

 might have reappeared in F,,. 



Taking all of the exi>eriments togi-ther the chief j)oint of interest 

 about them is, un(juesti«)nably, the failure of the larger form to reapjx-ar 

 in Fi in certain of the crosses. It is marked in the Flemi.sh-Polish 

 crosses and evident in the Fo family from iYl9. On the other hand it 

 does not seem to occur in the other Fo generation from the Flemish- 

 mixed cross, viz. that from iVl7. The non-appearance of an expected 

 class in F^ has occ^isionally been recorded for sundry characters, but the 

 only instance which we can recall in connection with size is tliat of 

 Ejist s Nicotiana cro.s.ses ('17), where, fiom the cross between N. Lanffs- 

 dorffii and N. alaUi, the small corolla length was recovered in F., with- 

 out difficulty while nothing appioaching the long coiolla of N. (data 

 reappeared. With this brief account of the crossing experiments we 

 may now proceed to discuss various points to which they have given rise. 



The G-rowtli Curve. We have alieady stated that the weight reconled 

 in our tables is the maximum weight attained by the animal during the 

 first twelve months of life^ Generally speaking, a rabbit grows rapidly 

 during the first half year of its existence, after which the monthly 

 increment graduall}^ becomes smaller. Somewhere between 7 and 

 10 months in the smaller breeds a maximum weight is reached, after 

 which there is usually some decline, connected probably with the ful- 

 filment of sexual maturity. Latei* <tn an incicase in w«'ight is again 



* With some ftw exceptions where ^rowtli was slow and maturity delayed. Tliese are 

 noted in Tables I — V, pp. 21—25. 



