490 



Mr. C T. Tlegan on the Origin and 



T venture to tliink that it is fairly certain that from some 

 form not very unlike Pstttodes the two groups typified by the 

 plaice and the sole have arisen, and tliat each of these has 

 split into two series, a sinistral and a destral. These con- 

 clusions are embodied in the following classification, and may 

 be expressed diagrammatically thus : — 



Bothinse. 



riatophriu.T. 



Paralichthiiwe. 



BotbidsB. 



Rhoinbosoleinne. 



Samarinae. 



Pleuronectinae 



Ojnoglossidae. 



Soleidae. 



Pleui'onecti formes. 



Soleifornies. 



\ 



Pleuronectuidea. 



Psettodid.'e. 



Pfiettodoidea. 



HeterosoQiata. 



Percoidea. 



I 



