CULTIVATION OB" MARINK AND FRESH-WATER ANIMALS IN JAPAN. 285 



into the Inland Sea by a narrow mouth, hardly a mile across, and is about 8 miles in 

 length by 6 miles of breadth. The differences between high and low tide marks 

 arc comparatively great here as in all parts of the Inland Sea, being 5 to 7 feet, ami 

 at low tide the whole of the bottom of the hay is exposed, leaving only four river 

 channels which run through the bay to its mouth. This Hat is the area utilized for the 

 cultivation of Area granosa. It seems that this idea was present in the minds of some 

 of the people us far hack as the sixties in the last century, ami was actually put in 

 practice by L869. At the beginning different individuals undertook the cultivation 

 by themselves, and the conflict of interests soon became the source of endless disputes. 

 People soon getting tired of this, it was agreed in L 886 to form an association in 

 which all the conflicting interests were amalgamated, and as this worked very smoothly, 

 it was organized in 1890 into a stock company. At present a little over s:-!() acres 

 of the bottom is utilized, the cultivated areas being scattered mostly along the southern 

 and western sides of the hay. The annual sale amounts to 75,000 to 100,000 bushels, 

 valued at more than 30,000 yen, and yielding a return of 40 to 60 per cent on the 

 capital invested. 



The method of culture is as follows: By September or October of every year, the 

 larvae of the mollusk, quitting their swimming stage, have become tiny shells not more 

 than 2 or 3 millimeters long, buried directly below the surface of the bottom mud. 

 These are collected from various parts of the hay by an ingenious instrument which 

 may lie described as a huge comb more than 6 feet lone-, being a series of short pieces 

 of wire with their points slightly bent, and planted with the other end on a piece of 

 board. This, being applied on another piece of plank, is forcibly pushed along the 

 mud bottom with the tooth part down, and all the tiny shells in the mud are caught 

 between the teeth of the comb and accumulated on the bent ends of the wire. These 

 are collected once in a while and put into a tub. after which another raking is gone 

 through. The distance between the wires regulates the size of the shells to be 

 caught. If the interval is large the shells caught are naturally large, and vice versa. 



These tiny shells collected from various parts of the bay are placed in the, culture 

 grounds. It has been found that the best size for starting culture is quite small— 

 that is, one which will go in to the number of 30,000 to 70,000 per "sho" (1.58 

 quarts or l.S liters). In order to distribute them over the ground allotted to them. 

 the little shells which have been collected are heaped up in a boat. One man rows 

 the boat along slowly and two others measure out the shells and throw them over- 

 board with wooden scoops. The quantity of shells that can lie most profitably put 

 into a unit area differs of course with the size and age of the shells, and has been 

 very carefully studied out. 



The tiny shells that in September are onl}- 2 to 3 millimeters across and run 30,000 

 to 70,0i)i) to a '"sho," grow 1>3 T the autumn of the next — that is, the second — year to 

 nearly 20 millimeters in length and run only 1,000 to a '"sho." In the autumn of the 

 third year their average length is already 32 millimeters and they run only 200 to a 

 Vsho/'and by the autumn of the fourth year they become -12 millimeters long or 

 only 12<) to a "sho." 



As the shells grow their number per unit area must be diminished to the proper 

 number determined by previous experience, and all the superfluous ones must be 

 removed to near lots. These culture grounds show therefore a large number of 



