INTRODUCTION. XVii 
DistRipution oF Percipz, 
The Centrarchide 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 day. The most generalized Centrarchids (Chenobrytius and Micropterus) are 
very similar to the Serranide. The Indo-Pacific Kuhlia and its fresh-water allies in 
Australia have been associated with the Centrarchide, but they present no very close 
affinity to the North-American fishes of the family. Fossil Centrarchide are found in 
the Eocene of North America. 
CyprinopontTIp#.—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, Plotosus, &c. The reasons which may be assigned for regarding 
the Cyprinodontide 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 
Cyprinodonts known are from fresh-water or estuarine deposits, chiefly lake deposits.” 
(3) The nearest allies of the Cyprinodontide appear to be the more generalized 
Holarctic fresh-water types Hsox and Uméra. 
BIOL. CENTR.-AMER., Pisces, Lebruary 1908. c 
