CENTEAECHID^. 41 



I supply that of lytJirocMoris, in allusion to the blood-red and pale-green 

 coloration. 



Xenotis lythrocliloris needs comparison chiefly with X. megalotis. The 

 body is elongate proportionally, somewhat as in the species of Apomotis, 

 bat the profile is quite steep. The back along the base of the dorsal 

 fin is unusually straight, not strongly bowed as in megalotis. Tho 

 colors are different in life ; there is more red on the cheeks and fins in 

 X. lythroGhloris, but the ground-color of the back is a decided olive- 

 green with blue spots. The belly, as in megalotis, is orange. The mem- 

 brane of the soft parts of the vertical fins in X. lythrocliloris is bright 

 orange-red. The spines are extremely short, the longest about equal to 

 length of snout. The most available distinctive point is in the oper- 

 cular flap, which is extremely long, longer than in megalotis or sanguino- 

 lentus, and entirely Mack, iiiitliout any trace of pale edging whatever, ex- 

 cept at base. In megalotis, the flap is conspicuously edged with paler. 



X. megalotis abounds most in ponds and still deep places in the 

 rivers. X. lythrochloris runs up the small brooks into places where it 

 and Apomotis cyanellus are the only Ceutrarchine inhabitants, whence it, 

 often comes to adorn the urchin's string in company with Semotilus 

 corporalis, Gatostomus teres, Gampostoma anomala, and other " boys' fish". 



25. XENOTIS AUEEOLUS, Jordan. 



1 Fomoils macrochira, Kirtland (1833), Bost. Journ. Nat. Hiat. iii, 469.— Stoker (1846), 

 Synopsis, 298 (not Icthelis niacrochira Raf.^Ze^JowJs neplielus Cope). 

 IcMJielis macrochlra, Jordan (1876), Bull. Buff. Nat. Hist. Soc. 92j Manual Vert. . 

 236(notof Raf.). 



Xenotis aureolus, Jordan (1877), Bull, ix, U. S. Nat. Mus. — . 



Body oblong, rather heavy forward ; the forehead usually quite con- 

 vex, but sometimes the profile straightish or almost concave; depth 

 about 2^ in length ; head 2| ; eye about as large as flap in adult, 4 in 

 head ; mouth moderate ; scales on cheeks rather large, in 5 or G rows. 



Fin-rays as in related species ; dorsal spines short, rather longer than 

 in X. lythrochloris, but scarcely longer than snout ; pectorals moderate ; 

 ventrals elongate. 



Colors very clear and translucent, the young almost transparent, the 

 adult lustrous, clear pale green above ; sides with much spotting of 

 golden orange or brassy, the spots numerous but not well defined, 

 shading into the green ; the orange predominating below ; the belly 

 clear orange ; some blue spotting on sides, a purplish-red lustre on the 

 sides in life, peculiar to this species. This disappears at death. 



