192 EXPLANATION OF PLATES. 



PLATE 5. 



Colored photographs of skins showing new color varieties of guinea-pigs. 

 FIG. 31. Silver cinnamon or red-eyed cinnamon. 



32. Red-and-pink-eyed black spotted with white. 



33. Pink-eyed golden agouti spotted with red and with white, hence a "tri- 



color." 



34. Albino with sooty fur and black pigmented extremities, similar to race B. 



PLATE 6. 



Femurs of hybrid guinea-pigs and of their parent races, natural size, to show extent of 

 variation. The longest and the shortest femur in each group of individuals is shown 

 with 3 or 4 others of intermediate length placed between them. In the left half of the 

 plate are shown the femurs of males, and in the right half the femurs of females. 

 Top row, Cavia cutleri. Second row, race B guinea-pigs. Third row, Fi hybrids pro- 

 duced by the cross of C. cutleri <? X race B 9 Fourth row, F 2 hybrids from the same 

 cross. 



PLATE 7. 



FIG. 35. A scale of grades used in describing the pattern of piebald rats. Rats like the 

 pictures toward the left of the scale are known to fanciers as "hooded"; the grade 

 at the extreme right would be called "Irish" by fanciers. 



36. Skins of a pair of rats and of their 9 young. One parent was an "Irish" rat, the 



other "hooded." Four of the young are hooded, five are Irish. Hooded is re- 

 cessive to Irish in crosses. The Irish parent in this case was a heterozygote. 

 Note individual variation in each group of young. 



37. A typical smooth-coated guinea-pig. 



38. A rough-coated guinea-pig, weU-rosetted, grade A. 



39. A poorly-rosetted rough guinea-pig, grade C. 



