THE AMERICAN TETRAGONOPTERINAE. 139 
Specimens examined. 
Number of 
Catalogue number specimens Size in mm. Locality Collector 
11434 I. Cotype 1 33 Matto Grosso 
10162 I. 1 37 Corumba Anisits 
3048 C. 1 39 Near Petas, Bolivia Haseman 
3049 C. + 38-41 Caceres Haseman 
3050 C. 16 35-44 Jauru Haseman 
3051 C. 4 38-43 Rio Santa Rita Haseman 
Head 3.25 to 3.5, depth 2.5 to 2.75; D. 10; A. 23-25; scales 5 or 6-30 to 
33-3.5; eye 2 to 2.5 in the head, interorbital 3. 
Compressed depth of head at the base of the occipital process 1.5 in the 
greatest depth. Preventral region flat, with sometimes a complete series of 
11 seales. Predorsal region rounded having a regular median series of 9 scales. 
Occipital process 4 in the distance between its base and the dorsal, bor- 
dered by three scales. Interorbital almost flat. Frontal fontanel triangular, 
narrower than and nine tenths as long as the parietals without the occipital 
groove. Second suborbital bordered behind and below by a naked margin, 
one half to one third of its own width. Mouth moderately large. Maxillary 
shorter than the eye, a little less than 3 in the head. Mandible heavy, equal 
to the eye. Premaxillary with five or six, 4- and 3-pointed teeth in the inner 
row, and three or four tricuspid ones in the outer row. Maxillary with two 
or three conical or tricuspid teeth. Dentary with a graduated series of four 
large, 3- to 5-pointed teeth, and a series of eight to twelve minute, conical ones 
on the side. 
Gill-rakers 7 + 13. 
Anal sheath short, consisting of 2 or 3 scales and covering the bases of 
the first four or five rays. Lateral line with pores on eight to ten scales. 
Origin of the dorsal equidistant from the snout and caudal, penultimate 
ray 2.5 in the longest, which is about one fourth of the length. Origin of the 
anal on the vertical from the last dorsal ray. Anal faleate. Ventrals on the 
vertical from the third scale in front of the dorsal. Ventrals just reaching the 
anal; pectorals just reaching the ventrals. 
Dorsal with a triangular black spot having the first ray for its base and 
the base of the fourth ray for its apex, the fin from the second to the eighth 
ray margined with black; the last two rays with scattered chromatophores. 
Humeral spot narrow, horizontally elongate, and enlarged posteriorly not quite 
connected with the black lateral stripe. No caudal spot. Somewhat silvery 
