THE DIAMOND-BACK TERRAPIN. 



I05 



The balance could then be used as salable stock whenever their size was great enough 

 to make them marketable. This would tend, then, to the selection by the terrapin 

 farmer of his best producers and fastest growers and in the course of years lead to a 

 race of quick -growing, large-framed, and highly productive terrapins. 



1911 BROOD. 



The 191 1 brood has consisted of two lots of terrapins, one fed two winters and 

 hibernating thereafter, the other hibernating each winter. The average growths of 

 these two groups differ about 1 2 mm. at any season of any year. The tendency, however, 

 as age increases, is toward a diminishing of this difference in the average growths. 

 The evidence brought to light in the 1910 brood that winter feeding tends toward earlier 

 productiveness is borne out in this brood also. In the fed lot the first egg laying occurred 



MM. 

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140 

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120 



110 

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 90 

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 20 

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1911 1912 1913 1914 1915 1916 1917 1318 1919 1920 



FlC. 81.— Growth of 1911 brood of original Carolina brood stock. Ecs production and hatch per 



female per year expressed, respectively, by figures on the curves. , Fed two winters; 



.hibernated; .estimated; * no males in this lot previous to this year; *» fertility 



modified by experimentation. 



in the fourth year, probably by only one female. Substantial output occurred in the 

 sixth year with an egg rate of 5.2 per female. The first production of the hibernating 

 lot occurred in the seventh year, but this was negligible — 0.2 egg per female. The second 

 egg laying in the hibernating stock was likewise small, the rate per female being 2 eggs. 

 This only further points out the desirability of winter feeding. It indicates, also, when 

 the results are compared with the 1910 brood lot which was fed only one winter, the 

 futility and extra cost of feeding terrapins more than one winter. It appears that the 

 1 910 winter-fed brood has shown that egg production and growth from one year's winter 

 feeding is much more desirable than the same from two years' winter feeding when 

 selection is not made of the brood stock. 



It may be added in this general connection that winter feeding does not tend 

 toward the development of weaker adults nor necessarily to animals more susceptible 

 to disease. It is true that young terrapins in the nursery house are subject to disease, 

 and there is occasionally considerable mortality from this cause. It apparently kills 

 many of those that would probably die from inherent weakness at best. There are 



