THE AMERICAN TETRAGONOPTERINAE. 



57 



Locality Collector 



Rio Puty St. John. 



San Goncallo, Rio Paranahyba St. John. 



Arroyo Trementina, Paraguay Anisits. 



Asuncion, Paraguay Anisits. 



Bahia Negra, Paraguay Anisits. 



Puerto Murtinho, Paraguay Anisits. 



Tumatumari, Brit. Guiana Eigenmann. 



Asuncion, Paraguay Haseman. 



Sapucay, Paraguay Haseman. 



Villa Hays, Paraguay Haseman. 



Corumba, Rio Paraguay Haseman. 



Rio Jauru, into Rio Paraguay Haseman. 



Caceres, Rio Paraguay Haseman. 



This species can always be readily distinguished by its great depth and 

 the two vertical humeral bars. The latter, though in some cases shadowy, are 

 evident in all of the specimens examined. 



Head 3-3.66; depth 1.6-1.8, rarely 2; D.ll; A. usually 36 or 37 3 ; scales 

 7 to 9-32 to 35-3 £-5- 4 Eye 2.25 in the young, 3 in the adult; interorbital less 

 than the eye in the young, greater than the eye in the adult. 



Deep, compressed, ventral profile evenly rounded from the tip of the lower 

 jaw to the origin of the anal; anal basis nearly straight, very steep. Dorsal 

 profile depressed over the eyes, humped to the dorsal; dorsal basis straight, 

 oblique; postdorsal to caudal nearly straight, oblique. Preventral area with a 

 median series of flat or slightly keeled scales, bordered on the sides by series 

 of angularly bent scales; postventral area with a median series of small, narrow 



1 Of these, twenty-five cf, judging by the anal armature, range from 60-90 mm., only three reach- 

 ing the latter size; the smallest female is SO mm. long, while thirty-six of them exceed the length of the 

 largest male. Of twelve taken at random six have thirty-six anal rays, four have thirty-seven, two 

 have thirty-eight. 



2 Of these, three have thirty-five anal rays, two have thirty-six, one has thirty-eight, and two have 

 thirty-nine; three have eight scales between the dorsal and lateral line, four have nine; all but one have 

 four and one half scales between the lateral line and the ventrals, one has five. The scales in the lateral 

 line are thirty-two in two, thirty-three in two, thirty-four in two, and thirty-five in two. 



3 Counting all rudimentary rays at the beginning and the double one at the end as one, out of fifty- 

 six specimens taken at random, four have thirty-four, nine thirty-five, eighteen thirty-six, fourteen thirty- 

 seven, seven thirty-eight, and four thirty-nine. 



4 In Amazonian specimens fifteen out of eighteen had seven scales between the origin of the dorsal 

 and the lateral line, the other three had eight. Out of twenty-four Amazonian specimens one has thirty- 

 one, one thirty-two, twelve have thirty-three, nine thirty-four, one has thirty-five. Thirteen out of 

 eighteen have three and one half scales between the ventrals and the lateral line, five have four. In the 

 specimens from Puerto Murtinho there is a larger number of scales above and below the lateral line. 

 Three out of seven have eight, the other four have nine scales between the dorsal and lateral line; six 

 out of seven have four scales between the lateral line and the anal and one has five. The scales in the 

 lateral line do not differ, 



