726 OCEANOGRAPHY 



Arrived at the culture grounds, they are scattered about, and soon 

 find their way into the mud of the bottom, which must, therefore, 

 be well adapted for the life of this mollusk. 



These shells are left for about three years. According to the 

 specimens given me by Mr. Fujita for examination, at the end of the 

 first year after transplanting they are 5.6 centimeters long; at the 

 end of the second year, 6.6 centimeters; at the end of the third 

 year, 9 centimetres; and at the end of the fouth year, 10 centi- 

 meters. In some parts growth is no doubt more rapid. 



Barnacles, "Jimegi ' (Balanus sp.) 



Further out in the same tide-flats, where the agemaki is cultivated 

 as described in the previous section, there are planted bunches of 

 bamboo collectors that look like the collectors for oyster-spat. Here, 

 however, they are to collect a species that is generally considered 

 injurious to cultural enterprises, -- namely, the barnacle. The col- 

 lectors are put up twice in a year, - - that is, in the spring and in late 

 August. The spring collectors begin to be taken dow^n after sixty 

 days, and it is thirty days more before they are all disposed of. The 

 autumn collectors are left standing one hundred days, after which 

 they are gradually taken away before the next March. The barnacles 

 that are attached to the collectors are beaten off and used as manure. 

 The annual yield is 400,000 bushels, fetching 30,000 yen. This cul- 

 tivation has been going on ever since 1830 or thereabouts. 



Miscellaneous 



"Tairagai" (Pinna japonica Reeve): The cultivation of Pinna is 

 confined to a small village on the Inland Sea, but it is interesting as 

 a specimen of what can be done in the way of mollusk-cultivation. 

 A little west of Onomichi, a large town on the north side of the Inland 

 Sea, there is a small village called Hosojima. It has only twenty- 

 five households, but each of these twenty-five possesses a small 

 Pinna culture-ground of its own, not more than fifty by thirty feet. 



Every October young Pinna, between seven and eight centimeters 

 long, are collected at a shoal near the village and put rather thickly 

 into the culture-grounds. The triangular shell, upright, with the acute 

 apex below, is buried in the mud to the edge of the shell and placed 

 in such a way that the hinge-line is toward the land and the open 

 gaping side toward the sea, thus preventing the muddy water that 

 runs down from entering the mantle-cavity of the mollusk. By 

 October of the next year the shells have increased about two and 

 one half times in size, although they are said to decrease in number 

 forty per cent, and will not grow much more, even if left longer. They 

 are then taken out, and new, young shells are put in their place. 



