CONTENTS. 



Kagt 



Preface 5 



Part I. — Ear-size 9-35 



Introduction 9 



Characteristics of lop-eared rabbits; sterility and its inheritance 9 



Growth-rate of lop-eared and of short-eared rabbits in size and in ear-length . la 



Matings of short-eared rabbits iuler se 14 



Matings of lop-eared rabbits inter se 16 



Cross I. — Lop-eared female X short-eared male 18 



Cross 2. — Short-eared female X lop-eared male 18 



Cross 3. — Belgian hare female X lop-eared male 20 



Cross 4. — Lop-eared female X half-blood lop male 21 



Cross 5. — Half-blood lop female X lop male 179 22 



Cross 6. — Half-blood lops mated ititer se 23 



Other matings of half-blood lops and additional Cross 6 matings 26 



Matings of three-quarter-blood lops 3I 



Cross 7. — Quarter-blood lop female X short-eared male 3i 



Cross 8. — Quarter-blood lop X three-quarter-blood lop 34 



Limitations of the data studied 34 



Conclusions 35 



Part II. — Weight 37-4° 



Part III. — Skeletal Dimensions 4i-44 



Part IV. — Color 45-68 



Color variation in relation to color factors 45 



Development of the factor hypothesis 46 



The general color factor, C 46 



The specific pigment factors, B, Br, and Y 46 



The intensity factor, I or D 46 



The factor for a pigment pattern of the individual hair, A 47 



The factor for uniformity of pigmentation, U, or spotting with white, S . . 47 

 The factor for extended distribution of black or brown, E, alternative with R 



(restricted distribution) 47 



Interrelations of factors E and U 48 



Interrelations of factors B, Br, and V 49 



Gametic structure and variation 49 



Gametic and zygotic formulae 5° 



Color varieties of the rabbit 5' 



Gray type 5 2 



Black type 5^ 



Yellow type 53 



White type 53 



Zygotic variation within each color variety 54 



Gray 54 



Blue-gray 60 



Black 61 



Blue 6a 



Yellow 63 



Sooty 64 



White 65 



The material basis of heredity factors 68 



Bibliography 69 



Description of Plates 7° 



3 





