260 MEMOIRS OF THE CARNEGIE MUSEUM. 



and by the absence of opercular and interopercular spines, which are present in the 

 other subfamilies. Its dorsal is farther forward than in the other members of the 

 family, again in this respect approaching the Siluridce. It resembles the rest of the 

 Pygidiidce in lacking an adipose fin and in the case of some specimens by having 

 a nasal barbel. I am not able to speak with certainty of its air-bladder. 2 



The principal subfamily is that of the Pygidiince. In addition to the main 

 characteristics of the family, the members of the subfamily have a barbel on the 

 anterior nostril, the gill-membranes are free from the isthmus, the teeth are in 

 bands. The genera of the Pygidiince differ but little from each other. Eremo- 

 philus, found on the plains of Bogota, has lost its ventrals; Hatcheria, living in the 

 Andes of Argentina and Chile, has an elongate dorsal fin, Scleronema from the 

 Uruguay has modified maxillaries and maxillary barbels. The main genus, Pygi- 

 dium, with sixty-three species, is found everywhere in the mountains and sparingly 

 in the lowlands. It attains the highest altitudes and flourishes in Lake Titicaca, 

 where it is a food-fish of importance. The only food-fish at Bogota is the closely 

 related Eremophilus, "El Capitan." Seventy-one of the known species of the 

 family belong to the subfamily Pygidiince. 



2 The genus Pariolius may be related to Nematogenys, but it is more likely to be related to Phrealo- 

 bius, Heptapicrus, Myoglanis, Leptorhamdia (for Leptoglanis which is pre-occupied), etc. The only speci- 

 men recorded has been lost. 



I. PARIOLIUS* Cope. 



Pariolius] Cope, Proc. Acad. Nat. Sci. Phila., 1871, p. 289. 



Type. — Pariolius arrnillatus Cope. 



Similar to Pygidium; no nasal barbel; a single barbel at the angle of the mouth; two pairs of mental 

 barbels; no armature on the opercles; gill-openings wide; teeth brush-like; origin of the dorsal behind that 

 of the ventrals; anus under dorsal; anal short. 



Little can be said about the relationship of this genus until its skull and air-bladder are examined. 

 It appears to be closely related to some members of the Pimelodince. There are no specimens available for 

 examination. It is known only from the type of the species, and that has been lost. 



Habitat. — Basin of Peruvian Amazons. 

 Pariolius arrnillatus Cope, I. c. (Ambyiacu); Eigenmann & Eigenmann, Proc. Cal. Acad. Sci. (2), II, 

 1889, p. 50; Occasional Papers Cal. Acad. Sci., I, 1890, p. 324; Proc. U. S. Nat. Mus., XIV, 1891, 

 p. 36; Eigenmann, Reports Princeton Univ. Exped. Patagonia, III, 1910, p. 398. 



"Head flat rounded, eyes small, superior, covered by the skin. Head 4.5 times in length to basis 

 of caudal fin. Depth at D. I. one-half length to basis pectoral fin; width of head two-thirds the same dis- 

 tance Intraorbital width 3.66 times in length of head. Maxillary and external mental barbels extending 

 beyond basis of pectoral; inner mental barbel one-half the same. Radii O. 7; P. 8; V. 6; A. 11; caudal 

 acuminate. Skin entirely smooth." 



* I am not sure of the origin of this generic name. Is it from the proper name Parioli, or from 

 n-ipaioXifu = to trick, hence a trickster or simulator, or from wapa = with, and dioXos = speckled"! 



