Axx.w.s X. V. ACAD. SCI. 



Vol. XXXI. plate ll 



>N 30 



' 



jgfe 



25 



^>'/ 



JT w 



22 



•* 17 



29 





26 





23 



-0 





1* 



27 







w 



Ml 



^^P *^P ft 



* 



18 



20 



21 



