2202 Bulletin ^7, United States National Museum. 



ward to anal ; about 20 in a vertical series. Body elongate, depressed 

 anteriorly; head especially very broad and flat; mouth large, broad, very 

 oblique, the maxillary reaching nearly or quite to opposite posterior mar- 

 gin of eye, its length 2 to 2f in head; lower jaw considerably projecting. 

 Teeth iu jaws all equal, in broad bands, the outer not at all enlarged. 

 Eye small, anterior, its length in adult 2 in interorbital width, which 

 width is about 3 in head ; a conspicuous knob at upper anterior and 

 posterior angles of orbit; preopercular spine well developed, strong, com- 

 pressed, directed downward and forward. Scales on head very small, 

 mostly cycloid, covering cheeks and opercles and upper part of head to 

 the eyes; scales on body smaller and smoother than in most other species, 

 those on belly much smaller than those on sides; scales on back and belly 

 cycloid, only those on sides distinctly ctenoid. Pectoral fins moderate, 

 reaching to near end of base of first dorsal, If in head; ventrals inserted 

 just behind axil, reaching halfway to vent, about 2 in head. Interspace 

 between dorsals about equal to diameter of eye. Soft dorsal and 

 anal short and high, very similar, coterminous; last ray of anal a little 

 longer than \ length of head; caudal peduncle long, a little shorter than 

 head. Caudal fin rounded, \\ in head. Color* dark, dull olivaceous 

 brown, paler below ; younger individuals mottled below with bluish and 

 speckled with dark brown ; sides without longitudinal stripes ; fins dusky, 

 all of them finely mottled and speckled with darker, the dark markings 

 on dorsal and anal forming undulated longitudinal stripes ; on pectorals 

 and ventrals forming dark bars. Distinguished from related species by 

 the larger mouth with small, equal teeth, and the small, smoothish scales. 

 Length about 18 inches. Streams of the Pacific Coast, from Sonora, south 

 to Panama; abundant in Rio Presidio, at Mazatlan, where the types of E. 

 wquidens were taken; not rare about Panama, (pictus, painted.) 



Eleotris pictus, KNER & STEINDACHNEB, Abh. Ah. Wiss. Wien 1864, 18, pi. 3, f. 1, Rio 



Bayano, near Panama; depth 6 to 7 in total length; scales 60. 

 Culius cequidens, JORDAN & GILBERT, Proc. U. S. Nat. Mus. 1881, 461, Rio Presidio, near 



Mazatlan. (Types, Nos. 28268 and 29240. Coll. Gilbert.) 

 Eleotrii cequidens JORDAN & EIGENMANN, I. c., 483. 



805. ALEXURUS, Jordan. 



Alcxurus, JORDAN, Proc. Gal. Ac. Sci. 3895, 512 (armiger). 



Body elongate, covered with small cycloid scales; preopercle with a 

 small, concealed, hooked spine at its angle, as in Eleotris; caudal fin 

 broad, its base with many procurrent rays. In other respects similar to 

 EU-otris. One species known; marine. (aXe^w, to defend; ovpd, tail, 

 from the caudal fulcra.) 



* A young example shows the following details of coloration in life: Blackish every- 

 where, sides with faint whitish streaks, along rows of scales a bro-td, blackish lateral 

 band occupying whole of side, back and belly paler, traces of faint dark cross bands; 

 caudal black, with a pale margin and some dark cross shades: pectorals, dorsals, and 

 ventrals more or less barred with black; preopercular spine well developed; a whitish 

 bar at base of caudal with a darker one before it. 



