122 TELEOSTEI: ACANTHOPTERI. — XX. 



tion. Thus Etheostoma is to he explained by the hypothesis of 

 the progressive atl:ipt;ition of the younj^ of certain J'erciruE to a 

 peculiar place of refuge and a peculiarly situated food supply. 

 These are the mountaineers among fishes. Forced from the j)opu- 

 lous 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 meagre living. Although diminished 

 in size by their constant struggle with the elements, they have d&- 

 veloped an activity and hardihood, 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 unich as concentrated fishes." 



Their colors are often very brilliant, the males of some species 

 being among the most brilliant fishes known. The sexes are usually 

 unlike ; the females being generally dull and speckled. They 

 usually prefer clear running water, where they lie on the bottom 

 concealed under stones, darting, when frightened or hungry, with 

 great velocity for a short distance, by a movement of the large pec- 

 torals, then stopping as suddenly. They rarely leave the Ijottom, 

 and are never seen suspended in the water. A few species f)refer 

 a sandy bottotn, where they lie buried in the sand, with only the 

 eyes visible. The Darters feed chiefly on the larva of Diptern. 

 The largest reach a length of 8 inches, but the average is alK)ut '2^ 

 inches. (The name EtheoMoma is said by Kafines(iue to mean 

 " various mouths " ((Ttpos, various ; oTo/xa, mouth ?), the three species 

 known to him caprodes, blcnnioidcs, and jiabellare, differing much 

 in this resjH'ct.) 



a. Hoily cxtn-niely elonf^ate, hyaline, subterete, the belly mosfly naked; 

 lateral line complete; head, long, pointed; gill membranes somewhat 

 united. 

 b. I'rcniaxillaries protractile; dorsal spines 7 to 11. 



c. Anal sjiine single; A. nearly as large as 2d D. (Ammocrypta ^ 

 Jordan = Pleurulepis liaird.) 

 d. Cheeks and opercles scaly. 



322. E. pellucidum Baird. Saxd Darter. Scales of body 

 not very rougii, only those along lateral line and on tail well imbri- 

 cated ; naj)e thinly scaled, becoming usually wholly naked on median 

 line; belly naked; maxillary barely reaching the large eye; P. 

 short. Translucent, finely dotted al)ove; a series of small s<iuare 

 olive blotches along back, and another along lateral line, the latter 

 connected by a gilt band ; fins pale. Head 4^ ; depth 7. D. X- 10. 

 A. I, 8. Scales 6-75 -X. Vert. 44. L. 2^. Ohio Valley and 

 N. W., al)Oundinrr in clear sandy streams, where it buries itself in 

 the sand by a sudden phuvje. ami lies with only the eyes uncovered. 

 ' iti-liOi, Muid ; Kpvnrot, eoucuuiud. 



