CONTENTS 



SECTION I 



Charles R. Stockard 



PAGE 



Introduction 3 



Statement of the problem 3 



Varieties of form among the dog breeds 9 



Resemblances of growth deviations in man to the modified forms in 



dog breeds 1- 



Modified types among other domestic animals 19 



Divergent forms among the vertebrate species 22 



Genetic mutations in dogs and the evolution of structurally modified 



species 24 



The primitive or wild ancestral dog type 28 



Hybridization for new combinations and recombinations of modified 



glands and type tendencies 37 



The pure breeds selected for hybridizing and their strongly con- 

 trasted characters 38 



SECTION II 



Charles R. Stockard 



Achondroplasia of the extremities; a definitely localized and highly altered 



growth reaction 45 



The genetics of limb achondroplasia in the bassethound 47 



Bassethound-shepherd hybrids 47 



The Fj bassethound-shepherd backerossed with the shepherd parent 



stock 57 



The Fi bassethound-shepherd backerossed with the bassethound 61 



The enhanced effects from two allelomorphs for achondroplasia as 



compared with the effects from only one such gene 64 



Bassethound-Saluki hybrids 69 



The Fj bassethound-Saluki hybrids 72 



The Fa bassethound-Saluki hybrids 74 



The Fi bassethound-Saluki backerossed with the Saluki 81 



The F x bassethound-Saluki backerossed with the bassethound 84 



xiii 



