THE AMERICAN TETRAGONOPTERINAE. 71 



Head 3.75; depth 2 on an average; D. 11; A 33-35; ' scales 5.5 or 6-33- 

 36-6. 2 Eye 2.75-4; interorbital 2.5. 



Very deep, compressed, profile slightly depressed over eye, ventral and 

 dorsal profiles about equally arched; preventral area narrowly rounded or 

 keeled; postventral area compressed; predorsal area sharply compressed and 

 keeled, with a few notched median scales, further forward the scales of the sides 

 are bent over the sharply compressed area; postdorsal area narrowly rounded. 



Occipital process narrow and long, two sevenths in the length to the dorsal, 

 bordered by four scales; interorbital broad, rounded; fontanels narrow, the 

 anterior less than half as long as the posterior which is continued as a groove 

 to the tip of the occipital process; second suborbital large, striate, leaving a 

 narrow naked area between it and the lower limb of the preopercle; maxillary 

 three in head, mandible 2.33. Usually four, rarely three or five teeth in the 

 outer series of the premaxillary, the second and third close together, the third 

 removed from the line of the others, five teeth in the inner series; two, rarely 

 three, in one case one and in one four teeth in the maxillary; lower jaw with 

 four graduated teeth and numerous minute ones. 



Gill-rakers 8 + 11, the longest two thirds as long as the pupil. 



Scales regularly imbricate, the exposed margin of those on the caudal 

 peduncle but little lower than that of those on middle of the sides, the width 

 of the exposed part a little more than half of the height; a few divergent striae, 

 the margins not crenate; nuchal scales not enlarged; anal sheath composed of 

 two series of scales in front, of a single one behind; lateral line but little decurved, 

 caudal lobes scaled for at least half their length. 



Dorsal about equidistant from tip of snout and base of caudal; its height 

 three and a half in the length, its tip when laid back removed by five scales 

 from the adipose. Lower caudal lobe somewhat the longer, three and a fourth 

 in the length; anal emarginate, origin of anal and last dorsal ray equidistant 

 from tip of snout ; origin of ventrals below the third scale in front of the dorsal, 

 equidistant from tip of snout and origin of last third of anal, reaching to or nearly 

 to the anal; pectorals reaching the tip of the axillary scale. 



No caudal spot; a well-defined, narrow, but very long, humeral spot reaching 

 from above the third to above the ninth scale of the lateral fine, on the upper 

 part of the series of scales above the lateral fine and the lower part of the series 



1 Of seventeen one has thirty-one, six have thirty-three, five have thirty-four, four have thirty-five 

 and one has thirty-six. 



2 Qf sixteen two have thirty-three, two thirty-four, seven thirty-five, five thirty-six. 



