THE AMERICAN TETRAGONOPTERINAE. 197 
groove. Second suborbital leaving a very narrow naked margin behind and 
below. Maxillary equal to the eye; mandible a fifth longer than the maxil- 
lary. Snout short. Lower jaw heavy. Mouth large. Premaxillary with an 
inner series of five 4- or 5-pointed teeth and an outer series of three or four 
tricuspid teeth. Maxillary with one to three 3- to 5-pointed teeth. Dentary 
with a graduated series of four large 5-pointed teeth followed by six or more 
minute conical ones on the side. 
Gill-rakers about 9 + 7. 
Anal sheath short, consisting of very small scales that do not reach the 
rays, about 9 in number, the first 6 together and the other 3 between the larger 
scales of the series just above the fin. Lateral line with pores on about 7 scales. 
Origin of the dorsal equidistant from the snout and the caudal, penulti- 
mate ray one third of the longest which is 3.25 in the length. Caudal probably 
about equal to the head. Origin of the anal on the vertical from the last dorsal 
ray or a little behind it. Anal emarginate. Ventrals on the vertical from the 
second scale in front of the dorsal. Ventrals just reaching the anal. Pectorals 
lapping half the length of the eye over the ventrals. 
Webs of the dorsal and sometimes those of the anterior 7 or 8 anal rays 
dusky. A diffuse dark spot covering a little more than the lower half of caudal 
peduncle. Upper half of caudal peduncle silvery. A very faint humeral spot. 
In the paratypes the second suborbital is not so wide as in the type and 
leaves a wider naked margin. 
20. Hypurssosprycon £os Durbin. 
Plate 28, fig. 4. 
Hyphessobrycon eos Durpin, Ann. Carnegie mus., 1909, 6, p. 69 (Between Potaro Landing & Kanga- 
ruma); ErcENMANN, Rept. Princeton univ. exped. Patagonia, 1910, 3, p. 437; Mem. Carnegie 
mus., 1912, 6, 341, pl.-1, fig. 2. 
Hasirat.— Guiana. 
Specimens examined. 
Number of 
Catalogue number specimens Size in mm. Locality Collector 
1194 C. Type 1 36 Between Potaro Landing & Shideler 
; Kangaruma 
1196 C., 11770 I. 24 35-42 Between Potaro Landing & Shideler 
Paratypes Kangaruma 
als (Cr, Tara 43 19-34 Tukeit Eigenmann 
Paratypes 
