78 



BRANCH MOLLUSCA 



dreds of vessels are engaged in this industry. Pearls of various shapes are 

 found. Their colors may be white, yellow, pink, blue, red, green, or even 



Fig. .5/.— .Some enemies of the oyster: 1, Drill (Crosalpinx einma); 

 2, mussel {ihi'lilitx n/idis); 3, Siihcllnria nih/ans; 4, periwinkle (Fiilavr 

 carica). (Report of Fish Commision for 1S07.) 



black Round lustrou.s white- ones an- most prized in Europe and America 

 but those of the yellowish hue arc preferred by Asiaties 



