H-:i;Tiu-n AND TIII 



21 



made specially to test this point and to learn something of the nature and I,.-., d.tarv 

 basis of sex. 



"The fertility of the crosses extends to the hybrids but ^-nrnilly i,,,i will, th- full 

 strength and constancy shown in the parent birds. I,, this reepect, the generic nnn 

 turtle) hybrids full more , less below the specifie hybrids, and j,, !,,!, elaHMH the 

 in fertility descend with the (leaves in relationship between the p.-nvnt sped* 

 The hybrids are more often mules Hum females. 11 



"Germs are as variable as thesnma itself. A ,-,.,-..|,i pn,,,f,,f ihi, | lind in theyo.mn .,f 

 si pair of homers (Dec-Jan. 1908-9). One of the y.mi K has jnvenal wing-ban like the 

 stock-dove (weakened), the other has i'eather> almost white ami the I.- .....Icte 



only traces." (K 12) 



It is clear then that the central feature of the author's extensive hyl.ridi/.ation 



studies the subject dealt with in this volume is the dei istration of o,. n , 



several grades of genetic non-e(iuiv;tlence and these strung upon a line; eonerrniim 

 which line he has obtained some definite and illuminating information leadim 

 the conclusion that germs subjected to certain procedures an i to on* 



another level of hereditary and developmental power. 



In the following summary the author has presented a situation re-peeling 

 fertility which he had found to be largely typical of many crosses of pi^-un - . namely, 

 lower fertility in the very first egg or eggs of the season; then a period of hinh 

 tility, followed by a prolonged period of much reduced fertility or . iute 



infertility in late summer or autumn: 



A male mourning-dove raised in 1897 \vas mated during the sea-mi of ix'.is \\ith ; , 

 ring-dove, but hatched nothing. The same bird was mated in April IX'.l'.t \\ith another 

 ring-dove. This pair had egg and young as follows: 



A 1. Apr. 23, 1X119; no development. 

 A 2. Apr. 2.5, 1S!I9; no development. 



B 1. May 30; hatched. 

 B 2. June 1 ; hatched. 



cfC 1. June 30; hatched. 

 cfC 2. July 2; hatched. 



l. Aug. 1; hatched. 

 c?D2. Aug. 3; hatched. 



El. Sept. 8; no development. 



E 2. Sept. 10; no development. 



I 1 ' 1. About Oct. 1; no development. 

 F 2. About Oct. 3; no development. 



G 1. Oct. 31; no development. 

 G 2. Nov. 2; no development. 



A I. M:iy 2!l. 1'JOII; no dcveli.pi,. 

 A 2. May 31, I'.IW; no development. 



'B I. .luilr Hi; hutched. 



? It 2. June IN; hatched (i\n i-.iiiail). 



(' 1. .Inl.v ::; poor incubation. 

 C 2. July 5; poor inciibatinn. 



cfDl. July 12; hatched. 

 I) 2. July II; hatched. 



K 1. Am.'. IN; no de\ c'lopmcni . 

 !; 2. AUK. 20: }<:<< 



I'M. I let. Ci; no ilevelo|ilnellt. 

 I J. ( ii-l. N: no de\elopm- 



< ! I. Jan. '.' I'.HII ; no ile\ . lopnient. 

 C 2. Jan. .' I'.IOI; no .1. \ elonmcnt. 



Here three successive pairs of eggs were hatched between .bine 1 I and Aiii;n-t Iv 

 The male continued to sit faithfully until the first \\eek in November, lie l-eiran to sit 



13 "In Plants, according to Swingle ami Webber ilS',17. p. :;ss . a-,, I, hi <lifl,r. 



Distinct genera usually yield no hybrids. Dixtiiicl x/wc/i .< of same genus often yield hybrids, t'uh 

 natural varieties, of same species generally yield hybrids." (All 



14 "See Buffon, vol. 3, p. o, supplement . Meckel refers to t his in vol. 1 . p. .'il'J. I >.-ivrii|iort concludes i In!.. 



in Poultry, Publication of the Carnegie Institution of Washington No. ">-'. IWo. p. HH) that "preiM,- truly 



important in inheritance as dominance." This is certainly true in pigeons. The same author lind> also tlur 

 jjroportion of the two sexes in hybrids is normal. Among pigeon hybrids this does not hold." 



16 This second list i.-, added by the editor from the author's data, for companion. Tin- r 

 Only males are known from crosses of the mourning-dove and the rini:-d.'\ 



