ioS 



BULLETIN OF THE BUREAU OF FISHERIES. 



accounted for. The severe winter of 19 17-18 may have retarded their develop- 

 ment somewhat, but the retardation in the average growth curve occurs before 

 that winter. It seems only further evidence that selectio'n of the large terrapins at 

 the beginning of the second year does not necessarily mean that those terrapins will 

 be the largest or best producers in the fifth or sixth year; that, as has been well shown 

 in the 1912 "selects" and "runts," selection of brood stock as early as the second year 

 is premature. The Texas brood of 191 3 does not show normal growth. Its average 

 growth has, however, been better than that of the Carolina brood which received the 

 same treatment. No eggs have been laid by the Texas stock. It may be that the 

 retarded average growth curve of the Texas stock is due to the fact that a number of 

 the larger terrapins of this lot were lost in a heavy storm in the summer of 1918. This 

 would also explain the late egg laying of this group. 



1914 BROOD. 



This lot of Carolina terrapins selected in the spring of 19 15 from thos.e terrapins 

 that had been fed during the previous winter has not shown more than ordinary growth 

 and did not produce eggs during 1919, the fifth year of its life. In 1920, the sixth year, 



IN. 

 5 



M M. 



130 



120 



110 



100 



90 



80 



70 



GO 



50 



4-0 



30 



20 



10 



1914 191.5 1916 1917 1918 1919 1920 



Fig. 84. — Growth of 1914 broods of original Carolina and Texas brood 

 stocks. Egg production and hatch per female per year expressed, 



respectively, by figures on the curve. , Offspring of Carolina 



brood stock, selected for large size in the spring of 1915; — 1 off- 

 spring of Texas brood stock, selected for large size in the spring of 1915. 



however, there was a small production of eggs. Early selection and the brood's later 

 retardation in average growth, which has been evidenced in lots previously discussed, 

 is further borne out here. The Texas brood of 1914 has been rather insignificant, in- 

 asmuch as it consisted of only five terrapins in 1919, the others having been shipped 

 to Texas. These five averaged somewhat larger than the Carolinas of the same stock, 

 but had not produced eggs up to 1920. To make room for other experimental lots 

 they have been shipped to Texas to be liberated. 



MORTALITY. 



As has been pointed out in the report of 191 7 mortality among adult terrapins is 

 very small. It does not amount to more than one-half of 1 per cent. In the young 

 the mortality runs higher, especially if the terrapins are winter-fed. The death rate 



