160 ARTHDI} WILLKV. 



stigmata. The, ori,siii of Bojanus contains a renal ealciilus, 2 C, reilueed by 

 one third. 



Fig. 13. — First two protostigniala at a slightly earlier stage than preceding, 

 showing the first in process of subdivision. From the right side. 



Fig. 14. — Change of shape of stigmata in the early adolescent period. The 

 figure represents a portion of the third and fourth rows of the right side of an 

 individual possessing eight rows on the right side, and six on the left. 



Fig. 15. — Formation of intercalary stigmata by abstriction (the figure does 

 not show the actual process of abstriction). From left side ; about ten rows 

 of stigmal a present in specimen. 



