Fig. 349. — Inheritance in collie dogs. A, Normal tan and black collie with 

 genes (vv) ; B, blue merle collie with genes (Vv) ; C, merle collie with defective 

 hearing and eyesight and genes (VV). The homozygous (VV) merle spotted 

 collies have defective sight and hearing, while in the heterozygous (Vv) condition 

 some ill eflfects are shown. The latter usually have such pale blue eyes as to be 

 wall-eyed, with a coat of intermediate blue merle. (After Mitchell. Reprinted 

 from United States Department of Agriculture Yearbook, Heredity in the Dog.) 



