THE CATFISHES OF VENEZUE.LA — ^^SCHULTZ 179 



DEFINITION OF TERMS 



Terms used in this report upon the catfishes of Venezuela are 

 defined as follows : 



Standard length is measured from tip of snout to midbase of caudal 

 fin; length of head is distance from tip of snout to rear end of operculum 

 unless otherwise specified, as in the family Loricariidae; width oj head 

 is across bony base just in front of insertion of first pectoral ray; 

 depth is greatest depth of body; snout is from tip of snout to front 

 of eye; distance between nostrils or nostrils to eye is measured from 

 edge of nasal openings; interorbital space is distance between the eyes; 

 postorbital length of head is distance from eye to rear end of operculum; 

 caudal peduncle length is measured from base of last anal ray to mid- 

 base of caudal fin; distances involving the anus are measured from 

 center of anus. 



Simple, flexible, nonpungent rays are represented by small and 

 pungent spines by large Roman numerals. Branched rays are indi- 

 cated by Arabic numerals. 



Other terms will be found self-explanatory as the species involved 

 are carefully studied. 



SUMMARY OF RESULTS IN THE MARACAIBO BASIN 



Catfishes belonging to 11 different families of Nematognathi were 

 collected in the Maracaibo Basin, as follows: Bagreidae, Pimelodidae, 

 Auchenipteridae, Ageneiosidae, Bunocephalidae, Cetopsidae, Pygidi- 

 idae, Doradidae, Callichthyidae, Astroblepidae, and Loricariidae. 



I was able to collect 51 species and subspecies in 36 genera from the 

 Maracaibo Basin and 8 species and subspecies in 7 genera in the 

 headwaters of the Orinoco system. For the Maracaibo Basin, 36 

 genera and 53 species and subspecies are known. A species of 

 Pygidium from above Merida in the Rio Chama system and Bagre 

 bagre were not collected by me. 



For all Venezuela, 127 species and subspecies in 63 genera are recog- 

 nized in this study. Without doubt these totals will be greatly in- 

 creased as soon as adequate collections are made in the Orinoco system 

 and in the coastal streams and when further collections are made in 

 the Maracaibo Basin. 



Certain elements among the Nematognathi are distinctive for the 

 Maracaibo Basin, but in general the fauna of this great basin has 

 much in common with that of the Orinoco and Magdalena systems. 



The number of genera and number of species of catfishes occurring 

 in the Maracaibo Basin of Venezuela are distributed among the 11 

 families as follows: 



The Bagreidae, marine catfishes, as was expected, had no distinctive 



