FISHERY RESOURCES OF THE PHILIPPINE ISLANDS. 299 



either with their toes or their liands, just as the fancy strikes them. Adult 

 shells are rather scarce on the public fishing grounds of those beds. I secured but 

 35 in one hour of fishing, but in ten minutes an owner of one of the planted 

 beds secured 100 adult shells for me. These nifasiued 118 to 135 millimeters 

 in their greatest diameter. 



The shell matures in three years. At the end of the iirst year it is (i2 

 to 83 centimeters in its largest diameter. The sexes are separate, the 

 eggs heing fertilized in the water. The mature ova have a decided resem- 

 blance to the form (in outline) of the mature shell, while the spermatozoa 

 have globular-shaped heads and extremely long tails, fully 10 to 15 

 times the length of the head. It is a comparatively easy matter to 

 fertilize the ripe ova under artificial conditions by taking the ripe 

 spermatozoa of the male in sea-water or normal salt solution. 



The artificial fertilization and cultivation of this important com- 

 mercial mollusk is well worth our careful consideration, and it is to be 

 hoped that with the opening of the salt-water aquarium and fish 

 hatcheries having running salt water, that the study of the life and 

 cultivation of this shell will be made with great care and detail. 



The food of the window-shell mollusk consists of small marine or- 

 ganisms, chiefly diatoms, which it collects from the water. The window- 

 shell mollusk apparently does not move about, but lies flat on the mud 

 on its convex, left side. The foot, instead of being a means of locomotion, 

 is used to keep the mud from the gills and other organs. 



QUANTITY OF SHELL AVAILABLE AND PRICES DEMANDED. 



The supply of this shell in the Philippines is so large that at no 

 place has it been found necessary to resort to diving for it, as is done 

 in India, as plenty of shell is secured by wading in water less than 1 

 meter in depth and feeling about with the toes. 



There are no laws regulating the gathering of window-shells, and so 

 far as we have been able to ascertain there are no municipal ordinances 

 relating to them. 



It is estimated that there are 5,000,000 of these window-shells used 

 each year in the City of Manila alone. A single lumber company of this 

 city in 1910 used 1,500,000. The demand is increasing. 



The price depends upon the size. Shells that will square 63 milli- 

 meters (2.5 inches) sell for 3 to 7 pesos (1.50 to 3.50 dollars) per 

 thousand; while the large ones which square 7.5 centimeters (3 inches) 

 sell for 8 to 10 pesos (4 to 5 dollars) per thousand. One window-shell 

 fisherman explained to me that he had three prices for the first-grade 

 shells. These were valued at 8 pesos per thousand to the Filipino, 10 

 pesos per thousand to the Spaniard, and 12 pesos per thousand to the 

 American. 



The Chinese traders do not hesitate to ask the amateur buyer 15 pesos 

 per thousand. The shells usually are sold in large baskets, each holding 

 10,000 pieces. 



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