DIAMOND-BACK TERRAPIN CULTURE 
27 
Terrapin Farm was patterned after the experimental plant of the Bureau of Fish- 
eries, and the success attained in raising terrapins compared very favorably with 
that of the Bureau of Fisheries. 
EXPLANATIONS 
Wherever the size of terrapins is mentioned in this paper it refers to the length 
along the median line of the plastron or lower shell, as this measurement has long 
been in use in classifying terrapins for the market. 
“Carolina terrapins,” when used in this paper to designate animals grown 
in captivity, refer to terrapins that actually are not of “pure blood,” because, as 
shown below, they are the result of a cross between the two closely related sub- 
species, Malaclemmys centrata centrata and M. centrata concentrata. This term is 
used for convenience in distinguishing the Atlantic-coast animals from the Texas- 
coast species, M. pileata littoraiis, as well as from certain hybrid lots also used in 
the experiments. 
DISTRIBUTION OF TERRAPINS 
Diamond-back terrapins occur on the coasts of the United States from Buzzards 
Bay, Mass., to Texas. Two species, divided into five subspecies, are recognized 
by Stejneger and Barbour (1923, pp. 131-132), as follows: The Carolina terrapin 
( Malaclemmys centrata centrata), ranging from central North Carolina to Florida; 
the Chesapeake terrapin (M. centrata concentrata ), ranging from Buzzards Bay to 
North Carolina; the Florida terrapin (M. pileata macro spxlota) , on the Gulf coast 
of Florida; the Louisiana terrapin (M. pileata pileata), ranging from the mouth of 
the Mississippi River eastward on the Gulf coast to Florida; and the Texas terrapin 
{M. pileata littoraiis), which inhabits the coast of Texas and the shores of the out- 
lying islands. The differences between the Chesapeake terrapin and those from 
the Gulf coast are quite pronounced; that is, the Gulf-coast terrapins have evident 
tubercles (humps) on the median line of the back, which are obsolete or wanting 
in the Atlantic species, and generally there are also differences in color that aid in 
separating the species. The differences between the Atlantic (Chesapeake and 
Carolina) terrapins, however, are slight. In general, the Carolina terrapin has a 
larger head, a blunter snout, and the sides (lateral outlines) of the carapace are more 
nearly parallel and less flaring posteriorly than in the Chesapeake terrapin. These 
differences usually are evident and are recognized by dealers. However, North 
Carolina is the geographical meeting place of the Chesapeake and Carolina terra- 
pins. Therefore, it is not surprising that some animals are seen from time to time 
that are difficult to place in either variety. 
The Atlantic varieties (Chesapeake and Carolina) of terrapins have both been 
used from the very beginning of the experimental work at Beaufort, for the original 
brood stock (still on hand) was obtained in part from Chesapeake Bay and in part 
from the general vicinity of Beaufort, where both varieties occur. These terrapins 
have been confined together in a small pen for almost a score of years, and there is 
not the slightest doubt that interbreeding is occurring freely. It may be stated here 
that apparently no inferior stock has resulted from this “crossbreeding,” as the 
offspring raised to maturity in captivity are a fine race of animals and superior in 
appearance to their parents. 
