MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES, VOL X. 



PLATE IV 



Pig. 21 a 



Fin. 21. 



Fig. aa tbi 



Fig. aa („,) 



Pig. 



Fig. 22 {d) 



n,l 







Pig. aa. 



Pig. 22 ( C ) 



Pig. 22 (/) 



Fig. 2a 





PHORONIS ARCHITECTA 



