Fig. 51. 



Fig. 50. 



Fig. 52. 









w^C^^JSH 









Wr-'~h j>2M 



■jf^l 



-I'J^Bn! 





la 











Fig. 54. 



Fig. 53. 



Figs. 51 and 52, magnification 18 x . Fig. 54, magnification 72 x . Figs. 51 and 52, 

 etched with acidified ferric chloride. Fig. 54, etched with ammonia and hydrogen 

 peroxide, followed by acidified ferric chloride. 



