PERIOD OF GESTATION. 401 



deer, eight months ; monkeys, seven months ; sheep 

 and goat, five months; sow, four months; beaver, 

 four months ; lion, one hundred and eight days ; puma, 

 seventy-nine days; dog, fox, and wolf, sixty-two to 

 sixty-three days ; cat, fifty days ; rabbit, thirty days ; 

 squirrel and rat, twenty-eight days ; Guinea-pig, twenty- 

 one days. 



A similar relation may be traced in the period of 

 incubation in birds, which is as follows : Turkey, 

 twenty-six to thirty days ; Guinea-hen, twenty-five to 

 twenty-six days ; pea-hen, twenty-eight to thirty days ; 

 ducks, twenty-five to thirty-two days ; geese, twenty- 

 seven to thirty-three days ; hens, nineteen to twenty- 

 four days, or an average of twenty-one ; pigeons, six- 

 teen to twenty days; canary-birds, thirteen to four- 

 teen days. Mr. Wright remarks that " cold weather, 

 or a prevailing east wind, will lengthen the time a 

 day or more, while warm weather and an attentive 

 sitter will hasten it ; stale eggs also hatch later than 

 fresh." 1 



He also states that the small breeds require less 

 time than the large breeds ; " Hamburgs generally 

 hatch at the expiration of the twentieth day, and 

 Game Bantams often even on the nineteenth." Man- 

 darin and Wood ducks " usually hatch in about twen- 

 ty-five days ; but something depends upon whether the 

 eggs are set under hens which, owing to the greater 

 heat of their bodies (at least we suppose so, reason- 

 ing generally), hatch from one to two days earlier 

 than if the same eggs are set under their natural 

 parent." * 



1 " Book of Poultry," p. 49. 2 Loc. cit., p. 556. 



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