272 EXPERIMENT STATION EECORD. 



maleX Hamburg female) the resulting F2 generatiou sbowed spangling and 

 nonspangling in both sexes. 



It is concluded that " a spangle factor is present in the Hamburg which is 

 transmitted in a sex-linked fashion, but evidently the pattern is affected by 

 other factors, as the spangling varies from a condition which is practically 

 identical with that of the pure Hamburg to one in which the pattern is dis- 

 turbed to a considerable degree, both in its purity and its distribution over the 

 body." 



In crossing a Black Bantam male anjl Fi hybrid female (from Black 

 maleXSeabright Bantam female) the resulting F2 generation showed a full 

 cock-feathered condition, a hen-feathered condition, and an intermediate con- 

 dition in the males. In crossing an Fi hybrid maleXFi hybrid female (both 

 from Seabright male X Black female) the resulting F2 generation showed a 

 full cock-feathered condition in all the males. In crossing an 'Fi hybrid 

 maleXFi hybrid female (both from Black maleXSeabright female) the re- 

 sulting F: generation showed the full cock-feathered, hen-feathered, and inter- 

 mediate conditions in the males. 



No conclusions are drawn, and it is proposed to continue these experiments. 



Changes in the secondary sexual characters of Gallinse, A. Pi:zARD ( Compf. 

 Rend. Acad. Sci. [Paris], 160 {1915), No. 7, pp. 260-263, fig. i».— The results of 

 experiments in ovariotomy with poultry indicate that spurs and the male 

 plumage may be developed in the female, but that the turgid comb and the 

 crow of the cock are characters peculiarly belonging to the male bird and do 

 not accompany ovariotomy as do the other secondary sexual characters. 



Sexual differentiation of pigeons' eggs {Carnegie Inst. Washington Year 

 Book, 13 {1914), PP- 117-119).— A brief account of the work of O. Riddle, who 

 has shown that " in pigeons, which usually lay two eggs at a time, commonly 

 one male and one female, eggs destined to produce males are smaller, and 

 have higher water content and smaller energy content, than those that produce 

 females." By the use of the bomb calorimeter it has been demonstrated " that 

 eggs destined to become males contain less stored energy than eggs destined 

 to develop into females. Whether the difference in energy content (however 

 it may have arisen) is the cause of the difference in the eventual sex or 

 whether it is induced by a certain difference in the unfertilized egg which deter- 

 mines the difference in storage metabolism is uncertain. There is reason 

 for thinking that the ova of birds are of two kinds, those destined to produce 

 males and those destined to produce females, and. there is also evidence that 

 the former contain a sex chromosome which the latter lacks. This difference 

 in the chromosomal content of the eggs destined to be males and females, 

 respectively, may therefore be the cause of the difference of energy content of 

 the two kinds of eggs." 



A study is being made to determine " whether a modification of the amount 

 of yolk stored in the egg can control the sex of the resultant chick. One result 

 secured is that when the female pigeon is subjected to alcohol vapor it lays 

 smaller eggs than normal. Other substances used (phloridziu and urotropin) 

 have caused a reduction in the fertility of the egg, but have not markedly 

 altered its size." 



It has further been found that " when two full sisters from such series are 

 hatched from the two eggs of a single clutch the first hatched behaves in copu- 

 lation as though it were a male. Also females hatched early in the season (the 

 period when most males are pi'oduced) are more masculine in behavior than are 

 their own sisters hatched late in the season. ... If extracts from the ovary 

 of a pigeon be injected into those females that are behaving like males, they 



