MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. VOL X 



PLATE 



Big. 17 () 



Fig. 18. 



Fig. 16 



Fig. 18 (6) 



Fig. 18 (c) 



Big. 18 {d) 



Fig. 18 (e) 



Fig. It). 



Fig. 1* / 



Fig. 20. 





Fig. 20 (a) 



Fig. ! 



Fig. 20 ( C ) 



Fig. 20 (<J) 



Fig. 20 (e) 



PHORONIS ARCHITECTA 



