DIAMOND-BACK TEKRAPIN CULTURE 
53 
time and are regarded as too expensive to use in practical terrapin culture. Oysters, 
also, are regarded as too expensive to use extensively, even though they produce 
rapid growth in the young animals. Although definite data are not available, it 
would appear advantageous to supplement fresh fish from time to time with oysters, 
clams, and crabs. 
CROWDING 
Various degrees of crowding have been tried in the tanks in the brooder house 
with the view of determining the space requirements of the young animals. In this 
series of experiments, which extended over three seasons (October to May, 1923 to 
1926), tanks 8 feet long and 20 inches broad, divided into four compartments, were 
used. Each compartment, therefore, had a floor space of about 20 by 24 inches. 
1919 IXO 1921 IX 2 1923 1921 1925 1925 1927 
Figure 9. — Rate of growth of two lots of terrapins of the 
brood of 1919. Line D represents offspring of domestic 
stock and line W offspring of wild stock 
Figure 10. — Rate of growth of two lots of hybrid terrapins 
of the brood of 1919. Line A represents a cross between 
Texas males and North Carolina females, and line B 
represents a cross between Carolina males and Texas 
females 
In some of the compartments 25 to 50 animals were confined, in others 100 were held, 
and in still others from 125 to 150 were placed. The rate of growth appears to be 
slightly in favor of the least crowding, for the average length of the 260 animals 
that survived was 34.8 millimeters. For the next degree of crowding, namely 100 
animals to a compartment, the average size of 877 surviving animals was 33 milli- 
meters, and for 1,082 surviving animals crowded to the extent of 125 to 150 to a 
compartment the average length attained was 31.1 millimeters. It is shown else- 
where that a somewhat similar relationship with respect to the rate of survival 
existed for the different groups of crowding. It appears reasonable to conclude, 
therefore, that it is feasible and economically advantageous to hold as many as 100 
young a n imals in a tank having a floor space of about 20 by 24 inches, but greater 
crowding appears to result in higher mortaility and slower growth. 
