THE AMERICAN TETRAGONOPTERINAE. 81 



predorsal area rounded, with an obscure median keel; eight scales between the 

 dorsal and the occipital process; postdorsal area rounded. 



Occipital process equal to about one fifth the distance from its base to 

 the dorsal, bordered by two or three scales on the sides; interorbital broad, 

 but little convex, the frontal fontanel narrower and about half as long as the 

 parietal; second suborbital very broad, covering the entire cheek or leaving a 

 very narrow naked border behind; maxillary but little longer than snout, 

 more than three in the length of the head ; four or five teeth in the front row of 

 the premaxillary, the third withdrawn from the line, the second and third and 

 sometimes the fourth close together; five teeth in the inner series; usually two 

 teeth on the maxillary; mandible with four large teeth and a number of minute 

 ones on the sides. 



Gill-rakers about 8 + 11, a little more than half the length of the pupil. 



Scales very regularly imbricate, the exposed edge of those on the caudal 

 peduncle about two thirds as high as that of the largest scale on the middle 

 of the sides; scales above the lateral line in specimens 50 mm. long with about 

 four nearly parallel striae, in the largest with 6-10 striae, frequently a notch 

 in the margin of the scale at the end of a line; anal sheath composed of two 

 or three series of small scales in front of a single series behind; caudal lobes 

 scaled to near their tip; lateral fine nearly straight from its sixth scale; axil- 

 lary scale well developed. 



Dorsal equidistant from tip of snout and base of caudal, its highest ray 

 nearly four in the length, its eighth ray about two thirds of the height of the 

 second. Anal emarginate in the young, the highest ray reaching base of fifth 

 from the last; not emarginate in the adult but the anterior rays two and a 

 half times as long as the one next to the last; origin of the ventrals equidistant 

 from tip of snout and tip of last anal ray, nearly or quite reaching the anal 

 in the young; pectorals beyond origin of ventrals for one or two scales. 



Dorsal, adipose, ventrals, and anal pink to orange; upper part of iris red, 

 the rest golden. A broad black band across the end of the caudal peduncle 

 and base of caudal, distal part of all the caudal rays light pink; in life a faint 

 vertically oval humeral spot; no silvery lateral band; color otherwise variable 

 in intensity with the locality, the margins of all the scales dark, the centers light ; 

 in life the younger ones have the adipose and caudal peduncle bright yellow. 



Vertebrae 12 + 16. 



Posterior air-bladder as wide as and three times as long as eye, twice as 

 long as the anterior, curved down behind to near the origin of the anal. 



Alimentary canal not quite equal to the length, without the caudal. 



