262 The Philippine Journal of Science 1916 



pearl. The triton shell is red on the inside and has been known 

 to yield red or pink pearls of value. This "pearl" proved to be 

 a bead cut from the large pearl shell, filed round, stained red, 

 and polished. These red "pearls" were very pretty, ranging in 

 color from pale pink to dark coral red. In size they were 

 usually equal to a very large pea; some were much smaller. 

 Their true value is perhaps 5 centavos each, the prices asked 

 are from 4 to 8 pesos. One jeweler paid 25 pesos for a small 

 lot, believing them to be true triton pearls as stated by the 

 vender. 



Another "pearl" examined was a large black one, which the 

 vender assured me came from a pinna shell. The pinna shell 

 is black on the inside and is known to produce black pearls. 

 This black "pearl" also proved to be a piece of shell made into 

 a bead, stained black, and polished. Like the red "pearl" it 

 failed to show any concentric formation, the shell layers extend- 

 ing straight through, instead of around, the central point. These 

 black "pearls" are usually the size of a pea or smaller. They 

 are almost perfectly round, are jet-black, and have a fine polish. 

 Their value is perhaps 3 centavos each; the price asked ranges 

 from 4 to 100 pesos. 



Among the fraudulent varieties of so-called pearls there are 

 at times small dark gray or blackish pearls which are more or 

 less flattened and lack the jet-black luster and perfect shape of 

 the so-called black pearls. These are true pearls, probably se- 

 cured from pinna shells, and possess some small value. They 

 may be easily distinguished from the false pearls by their color 

 and shape. Very small round pearls of a golden lusteV are 

 secured from a small avicula that has a beautiful golden luster 

 on the inside. The avicula shell is usually less than 6 centi- 

 meters in diameter, and I have never seen a pearl produced by 

 this shell that was larger than a number 6 shot. The big, 

 perfectly round yellow pearls offered for sale are usually frauds. 



The strombus shell (tacloban) produces pearls that are like 

 small china marbles — white, without luster, and of little value — 

 although they are usually of good shape. I have seen specimens 

 larger than pigeon eggs. 



THE TOP SHELL AND TURBAN SHELL FISHERIES 



The top shell, Trochus niloticus Linnaeus, and the turban shell, 

 Turbo marmoratus Linnaeus, are of primary importance in the 

 manufacture of buttons. Locally the top shell is known as the 

 "trocha," or chin leh, the turban shell as the "green snail," turbo, 

 or tua leh. These shells are fairly well described by their 



