CHAPTER IV. 



JAPANESE TURTLE-DOVES CROSSED WITH A DISTANTLY RELATED AND WITH 



A CLOSELY RELATED SPECIES. 1 



The present chapter and the three follow i,,-r ,,, ( | ( ,,| uit|l ,,. ,,,,,,| mu ., 

 crossing of the Japanese <>r Oriental turtledove. The data included U-.-.r upon 

 several different subjects, but chiefly will, "degree ,,f fertUity" in association uitl, 

 longevity and sex. The relation between "weak germs" : .i,.l season crowded 

 reproduction, inbreeding, and "mutations" are touched up<m ; ,t m;i ny point, \|| 

 of these topics are met with in the presrni rh.-iptcr. where t| l( . li r >t purp,. 

 record the data for the fertility, sex-ratio, and longevity of the off>priim of tin- 

 three species concerned when individuals are mated ( 1 i to their own kind, 

 related species, and (3) to an unrelated species. 



Different individuals of the species Turin,- ,;< ,,(<,lis. under even normal or 

 usual conditions, bestow very different possibilities of length of life upon their 

 offspring. When mated with their own species the ^roniie-i pair- of .Japa: 

 turtles should produce offspring with a life-term of perhaps :; to i:, yt an or m 

 Data on this point will be found toward the conclusion of the chapter. When 

 crosses are made, the "width of the cross" very measurably affect- j,, the \\i. 

 crosses) the number of eggs that will hatch, and also the length of life and tin 

 of the resulting offspring. By "width of cross" is meant the derive of phyl. 

 separation of the species used. 2 When a species closely related to T. ,.//.///,// 

 used as the other member of the cross, more of the eggs will hatch, the young will 

 live longer, and the sex-ratio in the offspring will be more nearly that normal I 

 mating of two T. orientalis than when a species distantly related to aru ///// 

 the other member of the cross. The species most closely related to T. o 

 is the European turtle-dove (Turtur turliir). and the most widely separated sp< 

 with which the Japanese turtle has been mated is the domestic pigeon. ('<>litinl,<i 

 admista, C. ajjlnisdom., C. tabellaritt, and ('. ijumnx were the common pigeon- i 

 used. The external characteristics of the Japanese turtle-dove are well shown in 

 pi. 1. The common pigeons are too well known to require special illu.-tratioii or 

 description here; one is shown with its hybrid mate in pi. ']. and several are (inured 

 in Volume I. There is no connected body of data to be presented on the length 

 of life of the common pigeon, but it is generally known that they easily attain 

 5 to 15 years. 



COMMON PIGEON X JAPANESE TURTLE-DOVE. 



Five female Japanese turtles were tested with 7 male common pigeon.-. They 

 formed 8 different matings which will be individually described: but the t:i! 

 which accompany these pages are relied upon to -Mipply many points of information 

 and to permit a closer view of the essential facts. 



From the first mating (admix/a <>ricnl<ili*. 1) Hi eggs were toted 'table 1 . 

 Four eggs showed no development ; '.\ produced embryo.- unable to complete develop- 



'Tho textual statement of this chapter hashivn written l.v the editor; all of the (aim: ,i ng records uaed 



here are those of the author. 



'The affinities and phytogeny of the pigeons are treated in Volume I of tb 



fication has been given at the close of Chapter II of this volume. 



3 



