INTRODUCTION. 



xvii 



DlSTRIBUIION OF PeECJD^. 



The Centrarchidse have probably originated in Eastern North America from marine 

 Perciform fishes with the habit of ascending rivers, as do the Bass (Morone) at the 

 present da)^ The most generalized Centrarchids {Chcenobryttus and Micropterus) are 

 very similar to the Serranidte. The Indo-Pacific Kuhlia and its fresh-water allies in 

 Australia have been associated with the Centrarchidae, but they present no very close 

 affinity to the North-American fishes of the family. Fossil Centrarchidge are found in 

 the Eocene of North America. 



Cypkikodoktid^. — At the present day many species of this family enter brackish or 

 salt water, but this habit is probably secondary, as in the case of the marine Cat-fishes 

 of the genera Arius, Plofosus, Sec. The reasons which may be assigned for regarding 

 the Cyprinodontidse as primarily a fresh-water family are as follows: — (1) Their 

 absence from the Australian Region, except for a species of Haplochilus in Celebes 

 and Lombok. (2) Several species have been found in European Oligocene and Miocene 

 deposits, and Dr. Smith Woodward has been kind enough to tell me that " all fossil 

 Cvprinodonts known are from fresh-water or estuarine deposits, chiefly lake deposits." 

 (3) The nearest allies of the Cyprinodontidse appear to be the more generalized 

 Holarctic fresh-water types Jisox and Umbra. 



BIOL. CEKTE.-.uiER., Pisces, Fehruciyij 190S. c 



