POULTRY NOTES — 1909. II3 



single" or "thickened single" or "single in front and thickened 

 behind." In all of these cases the remaining chickens in the 

 same families had either perfect or intermediate pea combs, 

 distinctly bearing in each case the pea characteristics. The 

 total number of offspring in each of these cases may be obtained 

 from Tables 4 and 5 (pages 91-92). All combs recorded as 

 "thickened single" or "almost single" bore no trace whatever of 

 definite lateral ridges such as are characteristic of a pea comb. 

 These combs were single in the important respect that they 

 lacked those parts which make a comb pea. They were not 

 perfect single combs, however, from the fancier's standpoint. 

 They were in almost every case too thick to be recorded as 

 perfect single combs. 



5. It is not intended to convey the idea in what has been 

 said above regarding comb inheritance in these hybrids that 

 the hybrid individuals bearing intermediate or single combs 

 will not behave in subsequent breeding essentially like those 

 having more perfect pea combs. This is a matter only to be 

 settled by experimental investigation. The points which it is 

 desired to ba'ing out, with as much emphasis as possible, are 

 (a) that there is no definite and perfect dominance of pea over 

 single comb in these F^ hybrids; but, (b) that, on the contrary, 

 the F-^ birds, which are heterozygotes, show objectively in regard 

 to comb form a perfectly graded series of comb types, ranging 

 from the perfect single to the perfect pea condition. These 

 facts, however, relate only to the somatic condition of the hy- 

 brids. All evidence obtained from the experimental study of 

 inheritance during recent years agrees in indicating that the 

 particular somatic condition of a character is an exceedingly 

 unreliable criterion of the probable behavior in breeding of the 

 individual organism with reference to that character. There 

 is every reason to suppose that this is true with reference to 

 comb inheritance. 



6. It is evident that the facts set forth in this section lend 

 themselves very readily to interpretation according to the prin- 

 ciple of the imperfection of dominance, lately so fully devel- 

 oped by Davenport* to account for the inheritance of a number 



*Davenport, C. B. Inheritance of Characteristics in Domestic Fowl. 

 Carnegie Inst, of Washington. Publ. No. 121, pp. iii -j- 100. 12 plates, 

 1910. 



