THE AMERICAN TETRAGONOPTERINAE. 141 
Origin of the dorsal the length of the eye farther from the snout than from 
the base of the caudal. The penultimate ray slightly more than half the length 
of the longest, which is about four and a half in the length. Caudal equal to 
the length of the head. Origin of anal on the vertical from the last dorsal ray 
or a little behind it. Anal broad, emarginate, the longest rays reaching the 
base of the last ray. Base of ventrals on the vertical from the second scale 
in front of the dorsal. Ventrals barely reaching the anal. Pectorals just reach- 
ing the ventrals. 
Distal two thirds to three fourths of dorsal black or blackish, the color 
more intense in males; a submarginal bar on the anal lobe, and the proximal 
half of the ventrals, black, the rest of the anal rays often tipped with black. 
No caudal spot. Humeral spot vertically elongate, a bright area in front and 
behind it. A wide light lateral stripe from the upper part of the eye to above 
the middle of the base of the caudal, paralleled below by a less distinct, brown 
stripe. A bright iridescent blue streak from the pectoral to the scale above 
the last anal ray. The scales of the sides below the lateral stripe, except those 
bearing the blue stripe, with a greenish iridescence. Scales of the back and 
sides above the lateral stripe deeply outlined with dusky. 
=> 3. HEMIGRAMMUS UNILINEATUS (Gill). 
Plate 21, fig. 5; Plate 78, fig. 8. 
Poecilurichthys Hemigrammus unilineatus Grut, Ann. Lye. nat. hist. N. Y., 1858, 6, p. 420 (Trinidad) ; 
GUnTuHER, Cat. fishes Brit. mus., 1864, 5, p. 317. 
Tetragonopterus unilineatus EIGENMANN & EIGENMANN, Proc. U. 8. N. M., 1891, 14, p. 54; Urey, 
Ann. N. Y. acad. sci., 1895, 8, p. 285, (Para, Brazil); Gi~Bert, Proc. Wash. acad. sci., 1900, 2, 
p- 163 (Pernambuco). 
Tetragonopterus (Hemigrammus) unilineatus Rucan, Proc. Zool. soc. London, 1906, p. 384 (Trinidad). 
Hemigrammus unilineatus EIGENMANN and Oct, Proce. U. 8. N. M., 1907, 33, p. 12 (Trinidad); Ercen- 
MANN, Rept. Princeton univ. exped. Patagonia, 1910, 3, p. 436; Mem. Carnegie mus., 1912, 5, 
p- 332; pl. 48, fig. 1; Exurs, Ann. Carnegie mus., 1911, 8, p. 162 (Braganga; Maciél, Rio Guaporé). 
Hasirat.— Trinidad, Guianas, and Amazons. 
Specimens examined. 
Number of | Length 
Catalogue number specimens in mm. Locality Collector 
5779 I. 5 28-38 Para, Brazil Hartt 
10801 I. 1 40 Los Castillas, Venezuela Riddle 
1440 C., 11898 I. 110 35-48 Creek in Moro Passage Shideler 
1441 C., 11899 I. 22 3141 Creek in Barima River Shideler 
1442 C., 11900 I, 86 23-48 Aruka River Shideler 
