EIGENMANN: THE PYGlDIIDyE, A FAMILY OF SOUTH AMERICAN CATFISHES. 305 



22. Pygidium quechuorum Steindachner. 

 Pygidium quechuorum Steindachner, Anz. Ak. Wiss. Wien, 1900, p. 207 (Arequipa I 

 Denksch. Ak. Wiss. Wien, LXXII, 1902, p. 137 (49 of separate), pi. IV, fig. 

 3-3a (Rio Chile, Arequipa); Eigenmann, Reports Princeton Univ. Exped. 

 Patagonia, III, 1910, p. 400. 

 Habitat. — Rio Chile at Arequipa, Peru. 



Fig. 11. Pygidium quechuorum Steindachner. Alter Steindachner. 



Known from the types, five specimens, 51-64 mm. long, in the Vienna Museum. 



Head about 5; depth 5.66-5.75 in total length; eyes very minute; interorbital 3 

 in the head, snout 3; width of head equals length of head or only very little less; 

 first pectoral ray not prolonged, the fin 1.5 in the head; maxillary barbel to some 

 part of the interorbital spines; origin of ventrals almost exactly in the middle; 

 origin of dorsal about equidistant from base of caudal and pectoral; origin of anal 

 behind the dorsal; caudal rounded or subtruncate; upper parts marbled; a narrow, 

 diffuse lateral band, which is sometimes faintly interrupted. 



Key to the Species of Pygidium from Venezuela, Colombia, Panama, and Ecuador. 

 a. Teeth incisors, apparently conic in the very young. 



b. Last dorsal ray over the last anal ray; distance between last anal ray and base of middle caudal 

 ray about 2.28 in its distance from the snout; distance between last anal ray and base of middle 

 caudal rays five and one-half in the length; obscure spots about as large as the eye evenly dis- 

 tributed over back and sides, no lateral band 23. laticeps (Kner) 



bb. Last dorsal ray over the anal. 



c. Sides with a lateral band or nearly confluent series of spots. 



d. Maxillary barbel extending beyond base of last pectoral ray; origin of ventrals equidis- 

 tant between caudal and some part of the opercular spines; distance between anal 

 and caudal four and one-half to four and three-fourths in the length; distance between 

 origin of dorsal and base of caudal about two in its distance from the snout; a narrow 

 lateral band, a variable number of small spots . 21. stellatum Eigenmann. 



(/(/. Maxillary barbel extending little beyond origin of the pectoral or shorter; a dark band or 

 series of spots below and another above the median band. 

 e. Origin of ventrals equidistant from caudal and middle of pectoral; distance between 

 anal and caudal five in the length; distance between origin of dorsal and caudal 

 a little more than t wo in its distance from the snout . . .25. chapmani Eigenmann. 

 ce. Origin of ventrals nearer head than caudal: distance between anal and caudal Eve 

 to five and one-half in the Length; distance between origin of dorsal and caudal 

 one and four-fifths to two in its distance from the snout. . 2lj. taenium (Kner). 



