ILLUSTRATIONS. 



Plate I. 



Landing pearl shell at Jolo. 



Plate II. 

 Fig. 1. Jolo pearling fleet. 



2. Pearl diver in the water. 



3. Pearl diver coming out of the water. 



Plate III. 



Philippine gold lip pearl shell (Uargaritifera maxima Jamson). 



Fig. 1. Inside view. 

 2. Outside view. 



Plate IV. 



Philippine black lip pearl shell {MargarHifera margaritifera Linnaeus). 



Fig. 1. Inside view. 

 2. Outside view. 



Plate V. 



Fig. 1. Section through center of Philippine pearl, showing an encysted cestode. 



2. Section through a Philippine pearl, showing a calcified cestode in the 



center. 



3. Section through a Philippine pearl which had a grain of sand in the 



center. It is also shown how a perfectly round pearl may become irreg- 

 ular and how it may be peeled to form a perfectly round pearl. 



Plate VI. 



Fig. 1. Culture pearls from the pearl farm in the Bay of Ago, Japan. 

 2. Pearls, found at Siasi Island in Tacloban shells. 



Text Figures. 



Fig. 1. Spermatozoa and ova of Philippine pearl oyster. 



(a) Micropyle, through wliich the spermatozoa enters the ova. 



(6) Nucleus. 



(c) Nucleolus. 



{d) Spermatozoa of male. 



2. Cestode from center of a Philippine pearl. 



3. A bit of shell in which a pearl valued at .500 pesos was hidden. The x 



indicates the spot where the pearl was hidden. 



4. The same shell as in fig. 3, but cracked open showing the pearl. 



5. Exact sizes of pearls from 0.1296 to 1.944 grams (2 to 30 grains) in weight. 



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