XXX11 

 GENALOGICAL TREE OF GANOIDS. 



The following table is added as a graphic illustration of the views just 

 unfolded : 



Skeleton cartilaginous.) Limbs squalo-acipenseroid. 



r n 



Noto(ohord persistent ; limbs squalo-acipenseroid. 



Mesopterygium developed. ) 



Skeleton osseous. 



} * (Mesopterygium ] 



^ O O B) , O 



o td 2 2 1 suppressed. * 



o ? o o P 



r 11 I * 



P go s 



x-s g g 



o 5 S s a 



i 



The left branches indicate the more generalized of the contrasted types. 

 The quasi-diagnostic phrases pertain to the succeeding forms, hypothetical 

 or known, till contradicted. The term " squalo-acipenseroid" is intended 

 for a type more generalized than the acipenseroid, and devoid of the special 

 modifications exhibited by the Chondrosteans. 



The relations between the various representatives of the Ganoid subclass 

 are very unequal, and they may be advantageously combined into groups 

 more comprehensive than orders. In fine, following out the views just 

 expressed, and subordinating the orders as recommended, we would have the 

 following sequence, starting with the most generalized: 



