THE AMERICAN TETRAGONOPTERINAE. 131 
Head 3.75-4; depth about 2.3-2.75; D. 11; A. 20-24; scales 5-32-3, 
6-8 with pores; eye 2.64; snout 4.12; interorbital about 2.5 in the head. 
Short, deep, especially in the female, not greatly compressed; ventral 
profile more regularly, and in the female more strongly arched than the dorsal 
profile; profile of head nearly straight, rising at the occipital process. Pre- 
ventral area broadly, the postventral more narrowly rounded; predorsal area 
keeled, with nine or ten scales. 
Occipital process about one fifth of the distance from its base to the origin 
of the dorsal, bordered on the side by about three scales; head convex, the 
fontanels broadest at the base of the occipital process, tapering regularly to 
the tip of the process and to a point over the anterior margin of the eye; frontal 
fontanel about as long as the parietal without the groove; second suborbital 
covering the entire cheek or leaving a very narrow naked area at its middle, 
a wider one at its anterior and posterior ends; mouth very oblique, the pre- 
maxillary with a very short antero-posterior extent, the maxillary regularly 
convex in front, broader than the preorbital, about 3 teeth in the front row of 
the premaxillary, about 8 in the second. Those of the outer series incisors with 
parallel margins, with a prominent broad central lobe and two receding shoulders, 
the teeth becoming conical toward the sides; the posterior series pointed incisors, 
or three pointed incisors with the middle point much the longer. Maxillary 
with a few large teeth near its upper angle and minute conical teeth scattered 
along nearly the entire margin; lower jaw with a single series of teeth, imper- 
fectly tricuspid, the points broad, not unlike those of the upper jaw, graduated, 
the lateral teeth minute, conical; snout and maxillary two and a fourth in head. 
Gill-rakers 8 + 12, a little over half the length of the eye. 
Seales cycloid, very regularly imbricate, with numerous striae parallel 
with their convex margin and few divergent striae; anal sheath of a single 
series of scales along the base of the anterior rays; caudal scaled for about 
one third of its length. 
Origin of dorsal and ventrals about equidistant from snout; pectorals 
reaching ventrals, ventrals to anal; anal emarginate. 
A humeral spot over the third and fourth scales of the lateral line; no 
caudal spot; dorsal, anal, and ventrals each with a conspicuous, jet-black 
spot; dorsal spot not extending upon the last ray, and leaving base and tips of 
rays hyaline; anal spot covering the third and fourth fifths (from the base) 
of the rays forming the anterior lobe; ventral spot leaving the outer and 
inner rays and bases and tips of all the rays hyaline. Very brilliant in life, 
