CULTIVATION OF MARINE AND FRESH-WATER ANIMALS IN JAPAN. 265 



which were laid in May or June, arc ready to hatch; and inasmuch as if small tor- 

 toises that have just emerged from the eggs arc allowed to get into the "parents' 

 pond*' they are devoured by their unnatural fathers and mothers, a special arrange- 

 ment has now to be put up to prevent this. Figure 1, plate ill. and the left side of the 

 plan in cut 2 are intended to show this arrangement. Long planks about 8 inches u ide 

 are put up lengthwise around the edge of the pond, leaving perhaps 1 foot"margin 

 between them and the water. Two successive planks are not placed contiguous, but 

 a space of about 3 feet is left between every two, and closed by a bamboo screen put 

 up in the shape of an arc of a circle, with its convexity toward the pond. Thus the 

 slope or the bank where the eggs have been deposited is completely cut off from the 

 pond itself. In the center of every pocket-like arched space made by a bamboo 

 screen an earthenware jar is placed with its top on the level of the ground, and some 

 water is put in it. This elaborate arrangement is for the reception of the young 

 tortoises, which, as soon as they break through the egg shells — those belonging to 

 the same deposit generally coming out at the same time — crawl up to the surface of 

 the ground by a hole or holes made by themselves, and go straight down the incline 

 toward the pond, as naturally as the duckling takes to the water. They are stopped, 

 however, in their downward hydrotaxic course by the planks put up, as stated before. 

 around the pond, and they crawl along the length of the planks and sooner or later 

 drop into the jars placed in the recesses between every two planks. A man going 

 around once or twice a day can easily collect from these jars all the young hatched 

 since the last visit. 



The young just hatched are put in a pond or ponds by themselves and given 

 finely chopped meat of a fish like the pilchard. This is continued through September. 

 In October Trionyx ceases to take food, and finally burrows into the muddy bottom 

 of the pond to hibernate, coming out only in April or May. The young are called 

 the first-year ones until they come out of their winter sleep, when they are called the 

 second-year young. At first the same kind of food is given these as that given to 

 the first-year young, but gradually this may be replaced by that given to older indi- 

 viduals, namely, any fish meat or crushed bivalves, etc. Figure 2, plate n, shows a lot 

 of the second-year young in August. From the third to the fifth year, inclusive, the 

 young need not be kept in ponds strictly according to age, but may be more or less 

 mixed, if necessary. The young of these years are also the best and most delicate 

 for eating and are the ones most sold in the market. In the sixth 3'ear they reach 

 maturity and may begin to deposit eggs, although not fully vigorous till two or three 

 years later. How old these snapping turtles live to be is not known. Those 1 foot 

 and more in length of carapace must be many years old. The following table gives 

 the average size of the carapace and the weight of the young: 



