IX] OF SPHERULITES OR CALCOSPHERITES 655 



Fig. 293. Calcospherites, or con- 

 cretions of calcium carbonate, 

 deposited in white of egg. 

 ^fter Harting. 



Fig. 294. A single 

 calcospherite, with 

 central "nucleus," 

 and striated, iride- 

 scent border. After 

 Harting. 



Fig. 295. Later stages in the same experiment- 





A B 



Fig. 2y(), A, Section of shell; B, Section of hinge-tooth of Mya. 

 After Carpenter. 



