228 MARINE FISHERIES OF NORTH CAROLINA 



winter, they would mostly remain active, feed and grow during the winter. 

 By the following spring they were about the size of year-old terrapin and 

 had thus been put forward about one year toward maturity. They could be 

 kept from hibernating in following winters and fed as during the first winter, 

 but the gain after the first winter was not considered sufficient to justify 

 the expense. 



In rearing terrapin in open pens, space requirements will depend in part 

 upon the nature of the area, and especially upon the clearness of the water 

 and the regularity of its change by tidal action or other cause. "The main 

 consideration," says Hildebrand (1929, p. 66), "is the provision of sufficient 

 room to furnish the necessary sanitation," He thought that under the con- 

 ditions existing at Beaufort 100 animals could safely be grown to maturity 

 in a pen 5x22 feet. This would allow about 1.6 square feet per terrapin. 



The sexes are externally indistinguishable in the first few years of life, 

 although adult males and females are markedly different in size and form. 

 While females may attain a length on the lower shell of 7 or 8 or even 

 nearly 9 inches, males rarely exceed 4^ inches in such measurement. They 

 are thus quite diminutive in comparison with the larger females with which 

 they may mate. Males are also flatter, and the top shell is rather more 

 wedge-shaped behind. The heads are smaller and more pointed, and the 

 tails are very much larger and heavier because of the included penis. It is 

 only when males are about four years old, with an undershell more than 

 three inches long, that they are readily distinguishable. 



Males grow more slowly, but females are too variable in growth for size 

 at a given early age to be a criterion of sex. In a particular brood, that of 

 19 12, about one-eighth of the females had attained the "legal" length of 5 

 inches (125 mm.) in the sixth year, when the largest male was 4 inches. 

 A little over 50 per cent of females had a 5-inch undershell in the eighth 

 year and 82 per cent in the thirteenth year. The smallest female of the lot 

 in that year was about 4% inches (115 mm.). A length of 6 inches was first 

 attained by a female in the thirteenth year. The gain in undershell length 

 per year after the eighth year is measured in millimeters, one or two. Unless 

 the rate of growth in nature is much more rapid than it is in confinement 

 with regular feeding, it may be assumed that a 7-or 8-inch female, rare in 

 nature, but of highest value in the market, is from 20 to 30 years old 

 at least. It would seem to require 10 to 20 or more years to add an inch 

 in length after about the tenth year (data gathered from tables in Hilde- 

 brand, 1929). 



The results obtained with different yearly broods were variable, but gen- 

 erally not markedly different. In the case of the brood of 19 10, however, 

 a female (or, perhaps, more than one) was over 6 inches in the sixth year. 

 Nine years later (1925) the largest female was 6% inches (165 mm.), 



