FRESH-WATER FISHES— MYERS 345 



the auditory apparatus. The ostariophysans are primarily a fresh- 

 water order and must have been since their pre-Eocene origin; out 

 of nearly 30 families and 4,500 or more species of them only 2 special- 

 ized families (the ariid and plotosid catfishes), comprising not over 150 

 species, are marine, and these beyond reasonable doubt are descended 

 from ancient fresh-water ancestors. To the Ostariophysi belong the 

 hordes of carps or minnows, suckers, loaches, characins, gymnotid 

 eels, and bewhiskered catfishes that swarm throughout the rivers and 

 lakes of all the continents except Australia. The only fresh-water 

 Ostariophysi of Australia and Madagascar are ariid and plotosid 

 catfishes that have reinvaded the rivers from the sea.' 



The remaining fresh-water groups of the primary division are quicldy 

 enumerated. The rather herringlike order Haplomi contains the 

 pikes or pickerels, the small mud minnows, and the Alaskan and 

 Siberian blackfish. To some extent transitional from the foregoing, 

 more primitive, bony fishes to the more highly developed, spiny- 

 rayed types, are the strange percopsids and pirate perches of North 

 America. Of the cyprinodonts I consider that only one family, the 

 North American cave fishes, belongs to the primary division. Of the 

 full}'' developed, perchlike groups we have the North American sun- 

 fishes or basses, the true perches of North America and Eurasia, and 

 the tropical nandids. Ending the series are the Old World tropical 

 labyrinth fishes and the isolated spiny-eels. 



The secondary division oj jresh-water fishes is composed of families 

 which, in general, behave like true fresh-water fishes, but whose 

 members show a less sharp restriction to fresh water. Among the 

 more important of them are the North American garpikes, the syn- 

 branchid eels, the cichlids, and the various families of topminnows or 

 cyprinodonts. Garpikes are known to enter the sea along the Gulf of 

 Mexico coast. Most cichlids can survive several hours or days in the 

 sea, and one species of Tilapia, collected in brackish water in Mozam- 

 bique, has been kept for months in sea water at the New York Aquar- 

 ium. Many cyprinodonts do not seem to be inconvenienced greatly 

 by salt water. Mollienisia latipinna enters the sea freely and multiplies 

 in brine ponds about Manila Bay, where it was accidentally introduced. 

 Metzelaar reported Rimilus from tide pools on Curagao, and certain 

 species of Fundulus and Cyprinodon live permanently on the seacoast 

 beyond reach of estuaries. The Challenger even caught a Fundulus 

 in a mid-Atlantic pelagic haul! It is evident that many species of this 

 secondary group might easily survive a short sea journey. This is 

 borne out by distributional fact. It is only members of the secondary 



• It seems probable that the supposed Bourbon catfish Laimumena, close to certain South American 

 trachycorystids, is based on mislabeled type specimens. 



