Heredity and sex . Fig. 68. — Dorset; male (horned) and female (horned). experiments also, in which the heredity of horns hasbeen examined. In some breeds of sheep, as in the Merinos andHerdwicks, horns are present in the males, absent inthe females (Fig. 67). In other breeds of sheep, asin Dorsets, both males and females have horns (). In still other breeds both sexes lack horns, asin some of the fat-tailed sheep of Africa and Asia(Fig. 69). Marshall has made experiments with Herdwicks —a race of sheep in which the rams have large, coiledhorns and the ewes are hornless. Three young rams
Heredity and sex . Fig. 68. — Dorset; male (horned) and female (horned). experiments also, in which the heredity of horns hasbeen examined. In some breeds of sheep, as in the Merinos andHerdwicks, horns are present in the males, absent inthe females (Fig. 67). In other breeds of sheep, asin Dorsets, both males and females have horns (). In still other breeds both sexes lack horns, asin some of the fat-tailed sheep of Africa and Asia(Fig. 69). Marshall has made experiments with Herdwicks —a race of sheep in which the rams have large, coiledhorns and the ewes are hornless. Three young rams(3, 4, and 5 months old) were castrated. The hornshad begun to grow (3, 41/2? and 6 inches long) at thetime of operating. They ceased to grow after theoperation. THE EFFECTS OF CASTRATION 135 A similar operation was also carried out on Herdwick ewe lambs (about 3 months old) wereoperated upon. After ovariotomy, the animals werekept for 17 months, but no horns appeared, althoughin one, small scurs
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Keywords: ., boo, bookcentury1900, bookdecade1910, booksubjectsex, bookyear1913
