772 EXPERIMENT STATION RECORD. 



as iu the case of somatic characters the correlation between ancestry and off- 

 spring decreases in geometric progi-ession, and the, regression is linear. Ac- 

 cordingly, there remains not the least antimony between the Mendelian theory 

 and the law of ancestral heredity, if attention is confined to gametic consti- 

 tution. 



" That ancestry does not matter if we know the gametic constitution of the 

 parents, that it does matter if we only know the somatic character of the 

 parents appears to be the solution of one of the difficulties which some have 

 found between the Mendelian and biometric methods of approaching the 

 subject." 



Studies of inheritance in rabbits, W. E. Castle et al. ( Carnegie Inst. Wash- 

 ington Pub. ll-'t, pp. 70, pis. If, figs. 3). — This paper reports studies on inherit- 

 ance of ear size, weight, skeletal dimensions, and color in rabbits. 



Reciprocal crosses between lop-eared and short-eared rabbits produced off- 

 spring with ears of intermediate length varying about the means of the parental 

 ear length, whether the larger parent was father or mother. A study of the 

 offspring of the primary cross-breds shows that this is a blend of the parental 

 characters and is permanent. The extreme range of variation in ear length 

 among short-eared rabbits was about 10 mm. ; in lop-eared rabbits from 20 to 

 30 mm. The form of the growth curve for ear length from the age of 2 weeks 

 on is convex upward, indicating a steady diminution in the daily growth incre- 

 ment. 



Statistics for size inheritance were not very satisfactory, as the size of a 

 growing rabbit varies greatly with the character of the food and other influ- 

 ences. Weight inheritance, skeletal dimensions, and proportions of skeleton 

 parts appeared to behave as blending characters. A'olume and weight of bones, 

 however, were uniformly less than mid-parental, a fact that can not be ex- 

 plained without further analysis. AVeights of the animals at different ages and 

 weight volume and linear dimensions of bones are presented in tabular form. 

 The linear dimensions in animals, as well as in plants, appeared to blend in 

 their inheritance. Dwarfuess is a discontinuous variation, while ordinary 

 variation iu height is blending. 



The gametic structure of 18 different known coml»inations of. color factors are 

 explained by means of foi'mulae similar to the structural formulae used iu 

 chemistry. Examples of formulae for zygotic combinations are also given. 

 Eight color factors are recognized in the gray rabbit, of which 32 combinations 

 are possible. The blue-gray rabbit differs from the gray in the intensity of its 

 pigmentation, which is always dilute, and 16 varieties are possible. Black 

 differs from gray only in the pattern factors and has 16 possible combinations. 

 Blue is a dilution of black with 8 possible varieties. Yellow differs from gray 

 only in the factor which governs the extension of black and brown pigmenta- 

 tion but not of yellow ; 16 combinations are possible. Sooty differs from the 

 yellow only in the pattern factor and has 8 possible combinations. The albino 

 differs from the pigmented in the common color factor, which is lacking or is 

 possessed only in a greatly modified form; if absent there are 16 combinations; 

 if present iu a modified form 32 combinations are possible. 



Mendelian inheritance of sex, A. L. Hagedoorn {Areh. Entivickl. Mcch. 

 Organ., 28 {1909), tio. 1, pp. l-S.'t, dgnis. 3).— This is a review of investigations 

 on this subject, together with a report of some experiments by the author. In 

 mating brown-red English game bantams with black-red bantams descended 

 from a pure strain, the author failed to produce female black-i-ed homozygotes. 

 but matings of a brown-red male with black-red hens of unknown origin re- 

 sulted in homozygous females and heterozygous males. 



