CULTIVATION OF MARINE AND FRESH-WATER ANIMALS IN JAPAN. 263 



Iti order to give a connected account of the raising of tortoises, we might begin 

 with a description of tin* pond for large breeding individuals, or "parents," and 

 with ;m account of egg-laying and hatching. 



The "parents' ponds" does not differ in any remarkable way from the general 

 plan of a pond given above. Usually one of the largest ponds is chosen, and it can 

 be distinguished from the others, because one or two of its slopes arc usually kept up 

 very carefully, while the other slopes or those of other ponds are apt to be worn by 

 rain and wind and to become rugged. These well-kept slopes are invariably on the 

 warmer sides, where the sun pours down its midsummer rays longest, and are carefully 

 worked over in the spring so that the tortoises will find it easy to dig holes in them. 

 In the breeding season these sides are seen to be covered with wire baskets which 

 mark the places where the eggs have been laid. 



Copulation takes place on the surface of the water in the spring. Ko-e- depo- 

 sition begins in the last part of May and continues up to the middle of August. 

 Bach female lays during that time two to four deposits, the number differing with 

 individuals and with years." The process of egg deposition is very interesting. A 

 female comes out of the water and wanders about a little while on the banks of the 

 pond in search of a suitable locality in which to deposit eggs. Having finally chosen 

 a spot, with her head directed up the bank she firmly implants her outstretched fore 

 feet on the earth, and during the whole operation never moves these. The process of 

 egg deposition, which takes altogether about twenty minutes, may be divided into 

 three portions occupying about the same length of time, namely: (1) digging a 

 hole, (2) dropping eggs in it, and (3) closing the hole. The digging of the hole is done 

 entirely with the hind legs. Each with its nails outstretched is moved firmly from side 

 to side that is, the right foot from right to left and the left from left to right, and the 

 two are worked in a regular alternation, while the body is swayed a little from side 

 to side, accompanying the motion of the legs. The force put in the lateral pressure 

 of the feet is so strong that the earth that has been dug out is sometimes thrown off 

 to a distance of 10 feet or more, although the largest part of it is heaped up around 

 the hole. Digging seems to be continued as long as there is any earth within the 

 reach of the legs to be brought up. The result is a squarish hole with the angles 

 rounded off, and although its size differs with the size of the female, it is generally 

 about 3 to 4 inches across at the entrance, with the depth and width inside about 4 

 inches or more. When digging is finished cues are dropped from the cloaca into the 

 hole, which naturally lies just below it. The eggs are heaped up without any order, 

 but, there being no chalaza?, the yolk is able to rotate in any direction, and the 

 blastoderm, having the least specific gravity, always occupies the highest spot of the 

 yolk in whatever position the egg may happen to be dropped. The eggs are generally 

 spherical in shape, although sometimes more or less oblate. Their diameter is in 

 the neighborhood of 20 millimeters, the largest being as large as 24 millimeters, the 

 others smaller according to the size of the females. The number of eggs in one 

 deposit varies from 17 or 18 up to 2S or more, the smaller individuals producing the 

 smaller number. 



"See my notes: "How many Unit's does the snapping turtle lay eggs in one season?" Zoological 

 Magazine, Vol. VII, p. 143, 1895. Tokyo. 



