MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES, VOL. VIII, 5TH MEM. 



PLATE VII. 



s 



Fv). 



Mg. 32. 



r 



'■ % 



Fig. 25. 



.>- 



Fig. U. 



2' 



'■' A 4 3 



Fig. 26. 



L. E. GRIFFIN, DEL. 



