THE AMERICAN TETRAGONOPTERINAE. 63 



4. Tetragonopterus gibbosus Steindachner. 



Tetragonoptcrus gibbosus Steindachner Siisswf. sudostl. Bras., 1876, 3, p. 4, pi. 1, fig. 1 (Rio Parahyba); 

 Eigenmann & Eigenmann, Proc. U. S. N. M., 1891, 14, p. 52; Ulhey, Ann. N. Y. acad. sci., 1895, 

 8, p. 277; Eigenmann, Rept. Princeton univ. exped. Patagonia, 1910, 3, p. 438. 



Habitat. — Parahyba. 



This species is known only from the types in the Vienna Museum. If the 

 caudal is naked as the artist has drawn it and if as Dr. Steindachner says the 

 "Oberkiefer, unter der Loupe gesehen, am vorderen Rande dicht mit Ziihnen 



besetzt " then this species does not belong to Tetragonopterus as here 



understood. In the characters other than the above and those mentioned in 

 the key this species closely resembles the Tetragonopterus chalceus which geo- 

 graphically is its closest neighbor. 



Head 3.6; depth 1.66-1.8; D. 10-11; A. 31-33; scales 6.5 or 7-28 or 

 29-3.5 to 4. Eye 2.2-2.4 in the head; interorbital 3 in the head. 



Much compressed, the profile little concave over eye, rising rapidly; ven- 

 tral profile regular to the anal; depth of caudal peduncle 5 in the greatest depth; 

 mouth oblique, terminal; 10-11 mandibular teeth, with the exception of the 

 outer pair more than twice as long and thick as the premaxillary teeth; second 

 suborbital nearly covering the cheek; origin of the dorsal a little in advance 

 of the middle; pectorals reaching a little beyond origin of the ventrals, equal 

 to the length of the head in the male, considerably shorter in the female, ventral 

 considerably in advance of the vertical from the dorsal, not reaching anal; 

 basis of anal scaled; its base half an orbital diameter longer than the head. 



Caudal only moderately forked and about as long as the head. Lateral 

 line rapidly descending on the first six scales; scales of the middle of the sides 

 very deep, radiae variable, 1-7; the three preventral series of scales very bluntly 

 keeled; the lateral keels forming the edge of the belly. Scales of the nape 

 apparently not decreasing in size. 



A light yellow lateral band; humeral and caudal spots very faint, the former 

 sometimes absent. 



2. Entomolepis, gen. nov. 



ivToitos, cut; \ewh, i}, scale. In allusion to the crenate scales. 



Type. — Tetragonopterus steindachneri Eigenmann. 



Caudal scaled; lateral line but little decurved, complete; the scales cre- 

 nate; an enlarged scale on either side of the occipital process; maxillary with few 



