85. PEKCID.E. 487 



are explained in a word by the hypothesis of the progressive adapta- 

 tion of the young of certain Percidcc to a peculiar place of refuge and a 

 peculiarly situated food supply. Perhaps we may without violence call 

 these the mountaineers among fishes. Forced from the populous and 

 fertile valleys of the river beds and lake bottoms, they have taken 

 refuge from their enemies in the rocky highlands, where the free waters 

 play in ceaseless torrents, and there they have wrested from stubborn 

 nature a meager living. Although diminished in size by their constant 

 struggle with the elements, they have developed an activity and hardi- 

 hood, a vigor of life and a glow of high color almost unknown among 

 the easier livers of the lower lands. * * * Notwithstanding their 

 trivial size, they do not seem to be dwarfed so much as concentrated 

 fishes." (Am. Nat. 1880, October, pp. 697-702.) 



The colors of the Etheosto matinee are usually very brilliant, species of 

 Pceciliclithys, Notlionotus, and Dlplesium being among the most brilliantly 

 colored fishes known 5 the sexual differences are often great, the females 

 being as a rule dull in color and more speckled or barred than the males. 

 Most of them prefer clear running water, where they lie on the bottom 

 concealed under stones, darting, when frightened or Jmugry, with great 

 velocity, for a short distance, by a powerful movement of the fan-shaped 

 pectorals, then stopping as suddenly. They rarely use the caudal fin 

 in swimming, and they are seldom seen moving or floating freely in the 

 water like most fishes. When at rest, they support themselves on their 

 expanded ventrals and anal fin. All of them can turn the head from 

 side to side, and they frequently lie with the head in a curved position 

 or partly on one side of the body. The species of Ammocrypta and 

 perhaps some of the others prefer a sandy bottom, where, by a sudden 

 plunge, the fish buries itself in the sand and remains quiescent for 

 hours at a time, with only its eyes and snout visible. The others lurk 

 in stony places, under rocks and weeds. Although more than usually 

 tenacious of vitality, the Darters, from their bottom life, are the first 

 to be disturbed by impurities in the water. All the Darters are car- 

 nivorous, feeding chiefly on the larvae of Diptera, and in their way vora- 

 cious. All are of small size; the largest (Pcrcina) reaches a length of 8 

 inches, while the smallest (Microperca) is probably the smallest spiny- 

 rayed fish known, barely attaining the length of an inch and a half. 

 They are of too small size to be used for food, although, according to 

 Eafinesque, "they are good to eat, fried." 



The PercincBiire represented in America by two genera, and in Europe 

 by the same two and three others Acerina, Percarlna, and Aspro the 



