104 



BULLETIN OK THE BUREAU OF FISHERIES. 



ever, the brood surpassed its best record again by laying 140 eggs, of which 125 hatched 

 giving an average egg record of 35 per female and an average hatch of 31.2 young per 

 female. There were 16 nests found in 1919 and 19 in 1920, indicating quite conclusively 

 that all females of the 1909 brood laid at least four times and that three of them laid 

 five times in 1 920. Growth after the seventh year is small, but it is attended by increasing 

 fecundity. The cause of the high percentage of infertile eggs in the first year of laying 

 of this brood may be due to the fact that the males of the brood were not mature. 

 However, the following year the larger part of the eggs by far was fertile. 



1910 BROOD. 



Two lots of the 19 10 brood were set apart in the fall of 1910, one fed the first winter, 

 the other allowed to hibernate. A comparison of the average growth of these two lots 

 indicates that the first lot, winter-fed, by average measurement, arrived at the 5-inch 



MM. 



150 



140 



130 



120 



110 



100 



90 



80 



70 



60 



50 



40 



30 



20 



10 



1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 19^0 



Fig. 80. — Growth of 1910 brood of original Carolina brood stock. Egg production and hatch per female 



per year expressed, respectively, by figures on the curves.  — , Fed two winters and selected for 



large size in the spring of 1914; , fed one winter; . hibernated. 



mark and to egg-laying one year before those that hibernated, and also that the egg-laving 

 began at a higher rate and continued higher than that of the hibernated group (fig. 80). 

 In early spring (1915) 8 males and 25 females were selected for size from the fed lot and 

 kept in a separate inclosure. Their egg production in the second year of their laying 

 was 16.7 per female, a much greater productiveness than was made either by the ordi- 

 nary lot of fed terrapins from which the selected individuals were chosen or by the lot of 

 hibernating terrapins three years later in 19 19. 



These facts indicate that for the commercial terrapin culturist it would pay more 

 in a series of years to hold the largest and fastest growing stock as breeders rather than 

 to pick here and there for his commercial sales. He could hold such brood stock over a 

 long period of years and feel certain that maximum production would not come before 

 at least 15 or 20 years. He would know, also, that the egg production of his breeders 

 was as large as could be obtained. Thus, each year a certain number of the best grown 

 females of 3 vears or older could be chosen to be held as the established brood stock. 



