452 



The Evolution of Fishes 



as deep, others arrow-shaped, and every intermediate form being 

 represented. An offshoot from this hne is the bowfin (Anna 

 calva), among the Ganoids the closest hving ahy of the bony 



Fin. 2()1. — An ancirnt Ganr.id fish, Plnli/sotiius gibbosus Blainville. r'amiiy 

 Plah/somidn'. (Alter Woodward.) 



fishes, sliowing thstinct affinities with the great grouji to which 

 the herring and salmon bckjng. \ear relatives of the bowfin 

 ilourished in the !\Iesozoic, among them some with a forked tail. 





Fig 2ri2. — A living Ganoid fi.sh, the Short-nosed Oar, Lrpixnslciis plalystomus 

 Rafinesque. Lake Erie. 



and some Avith a very long one. From Ganoids of this tvpe 

 the vast majority of recent fishes may be descended. 



Another branch of Ganoids, divergent from both garfish and 

 bowfin and not recently from the same primitive stock, included 

 the sturgeons (Acipenser, Scaphirhynchns, Kcsslcna) and the 

 paddle-fishes (Po/_vo(ion iind Pscphurus). All these are regarded 

 by Woodward as degenerate descendants of the earliest Ganoids. 

 Palceoniscida:, of Devonian and Carboniferous time. 



