58 
BULLETIN OP THE BUREAU OF FISHERIES 
of age have been retaken. The recaptured animals had gained growth at about the 
same rate as the fastest growing ones of the same age that were raised in captivity. 
In the almost total absence of data on the rate of growth in nature, a comparison of 
the rate of growth of domestic and wild animals can not be given. Neither will it 
be known, until much more information is obtained, whether an equally large per- 
centage of wild animals are slow growers or runts as among domestic ones. There- 
fore, it is not yet known what influence, if any, domestication has on the rate of 
growth. 
Male terrapins have been omitted in the discussions on growth because they 
do not reach a large size and are of comparatively little value on the market. The 
sexes can not be distinguished in young terrapins until a length of about 3 inches or 
more is attained. For this reason the sexes are not listed separately in the accompany- 
ing tables until they have attained a considerable size. It is not evident that there 
is a difference in the rate of growth with respect to the sexes until they become dis- 
tinguishable. Thereafter the males appear to grow less rapidly, and consequently 
they are soon much smaller than the females. It is fortunate, from an economic 
point of view, as pointed out eleswhere, that the males appear to be greatly in the 
minority, for the largest one of which a record is on hand was 4 % inches long and 
the largest one among the domestic animals has a length of only 4% inches. The 
average size of adult males appears to be around 4 inches, and a considerable per- 
centage apparently never exceeds a length of 3 % inches. 
CONCLUSIONS 
It is evident from the foregoing discussion and the data presented that the 
chief problem of the terrapin culturist is the elimination of the runty and slow- 
growing animals. It has been shown that this can not be done through selection 
at an early age. Therefore, the problem apparently must be solved, if in fact it 
can be solved, through selective breeding. Experiments along that line are under 
way, but owing to the slow growth and the long time it takes terrapins to mature 
no definite results have been obtained to the present time (1928). Slow growth, 
late maturity, and animals of comparatively small size may not be of importance 
in the case of terrapins that are liberated and attain their growth in nature, but they 
are of extremely great importance to the terrapin farmer, who would of necessity 
be interested in as quick a turnover as possible and in the production of large animals 
that would bring a fancy price on the market. It has been shown that little growth 
is gained after the animals reach an age of 8 to 10 years, and the writer believes that 
it would not be profitable in terrapin farming to retain the animals longer, but that 
they should be disposed of at about that age regardless of size. 
