ATOPICHTHYS ESUNCULUS. 327 



Atopichthys esunculus sp. u. 



Plate LXV. fijs. 2, 2 a. 



D. 16-17; A. 8; P. 13; V. 8; C. 25. 



The form of this species closely resembles that of E. Costal as given by 

 Kaup, 1856, Cat. Apodal Fish, PI. XVI., fig. 3. 



The body is much compressed and attains its greatest depth, which is 

 about one sei'enth of the total length, at about three fourths of tiie distance 

 from the sncut to the tail, whence it gradually tapers to the head. Body 

 cavity very long, close upon seven eighths of the total. 



Head small, comparatively narrow, subconical, near one twelfth of tho 

 entire length, convex on the crown and on the top of the snout, moderately 

 blunt and rounded in front. Somewhat pointed, arching upward above the 

 mouth, shorter than the eye. Eye lai'ge, one third as long as the head, 

 longer than the snout, lateral. Mouth large ; maxillary extending below 

 little more than half of the eye. Teeth on the lower jaw large, slender, 

 acicular, compressed, inclined forward ; on the upper jaw smaller, very 

 slender, vertically directed. Nostrils small, in front of the eyes, midway 

 to the end of the snout. Gill openings wide, passing from in front of the 

 pectoral base down and forward to below the eyes. 



Pectoral fins small, of about thirteen rays, reaching the eye. 



Ventrals small, of ^ight rays, bases below the thirty-fifth transverse 

 muscle segment, which is nearly in the middle of the length. 



Dorsal of sixteen or seventeen rays, shorter backward, the first above 

 the fifty-fourth muscle-segment or about the beginning of the posterior 

 fourth of the total. Anal short, of eight rays, close to the caudal, originat- 

 ing below the sixty-seventh muscle-band. Caudal short, rather deep, 

 deeply forked, of twenty-five rays. Vent below the sixty-sixth muscle- 

 segment. 



Translucent or transparent ; with black pigment in a streak of puncticu- 

 lations along the upper edge of the intestine, in a dot on the caudal pedicel 

 forward of the bases of the rays, and in a transverse band across the bases 

 of eight or ten of the inner rays of the caudal. 



"Off Acapulco, Apr. 13, 1891." 



