42 



CEYLON PEARL OYSTER REPORT. 



Fig. 



12. 



13. 

 14. 

 15. 



16. 



17. 



Three calcospherules from the insertion of anterior levator muscle ; a, simple ; b, compound ; 



c, optical section showing pearl layers (a) being deposited round calcospherule. 

 Diagram showing position of two irregular compound muscle pearls in 2nd and 3rd pallial muscle 



insertions ; a and b show the two pearls, slightly enlarged. 

 Diagram showing two rows of muscle-scars, the outer being the present functional ones ; 



a marks the position of a muscle-pearl on the site of a former muscle-insertion (palpar region). 

 Six cyst pearls in the mantle of the posterior ear, left side ; four others lay in a corresponding 



position on right side. 

 Two cyst pearls in mantle, posterior to dorsal end of adductor muscle. 

 Six cyst pearls, misshapen through mutual pressure, in the mantle of the posterior ear. 



Figs. 13 to 17 are about natural size. 



Section of a Tay pearl in the natural condition magnified. (After M'Intush, from ' The Zoologist,' 

 for February, 1904 lent by the courtesy of the Publishers.) 



