388 BULLETIN OF THE BUREAU OF FISHERIES. 
still very small at this stage of development, it is difficult to select those which 
are satisfactory in every respect, and only those furnished with the better 
caudal fins, such as they are, are picked out. .Ten days later the second selec- 
tion takes place, when those having any irregularities on the back are thrown 
into a mud pond and put aside. Again, ten days later, the third selection is 
made and the fish are grouped together according to their size. And yet, about 
ten days after this, the fourth and last selection comes, when particular atten- 
tion is paid to the form of the caudal fin. The fish are for the first time put up 
for sale when the third selection is over. 
After the first selection the young are put into two concrete ponds, each 
of which is of the same size as the former one, and in the second selection they 
are distributed into three ponds of this same size. The area of these ponds . 
would not be large enough for the original number of fish, but the number has 
been reduced as the inferior breeds were eliminated. To every twenty of the 
fish hatched in the beginning of May is givena space of one tsubo (3.3058 square 
meters), and when the cold weather comes they are removed either to a mud 
pond or to a hibernacle (i. e., wintering pond). The latter, which is made 
entirely of concrete and has a depth of 6 to 8 sun (18.2 to 24.2 centimeters), 
is provided with a lid, and the whole is again covered with an inclined roof open- 
ing toward the south, with one end coming down to the north edge of the 
pond. When the weather is warm, the lid is partially lifted up so as to admit 
the sun’s rays into the pond from the south. The water sometimes becomes 
foul through the putrefaction of fish food and from other causes, in which case 
a basket having its lower part covered with gauze is immersed into the con- 
cavity of the pond and by means of a rubber siphon put into the basket the foul 
water is drawn out, to be replaced by fresh water. The fish in the second and 
third years should have a space of one tsubo at least for every twenty of them. 
In the first year the fish attain in eight or nine months the size of 2 sun 5 
bu (7.5 centimeters) from the snout to the extremity of the tail; in the second 
year they attain in the same length of time the size of 4 sun (14 centimeters) ; 
in the third year, 5 sun (15 centimeters); in the fourth year, 5 sun 5 bu (16.5 
centimeters), and in the fifth year, 6 sun (18.2 centimeters). The fish that 
are kept four or five years are the only ones fetching a very high price in the 
market. 
RYUKIN. 
Being naturally very strong and healthy, the ryukin is much in demand 
abroad and is exported in large numbers. At home, also, this variety is a great 
favorite, and as such is kept in the ponds. Those having the longest caudal 
fin and called ‘“‘ohiki,”’ viz, ‘‘tail trailers,’ require at least four years for their 
full development. The superior kind has a head broad in front but not angu- 
