EIGENMANN : FRESH WATER FISHES. 



335 



tion into the La Plata basin from the Amazon by some inland route, and 

 that for the thirty and more genera at least, that are absent from this area 

 and from the San Francisco, this territory could not have been the center 

 of dispersal. 



The fifty genera thus present in the Amazon and La Plata and absent 

 from the coastal rivers exceed the total number of genera recorded from 

 them. 



The following genera found in the La Plata and Amazon have not 

 been found in the coastwise streams. Those not recorded from the 

 Magdalena are marked + ; those not in the San Francisco X. 



X + BuuocepJialits, 



X + Dysichthys, 

 Pinielodus, 



X + Liiciopiinelodus, 

 Pseudopiafy stoma, 



X + Paulesca, 



X Soriibim, 



? Doras, 

 + Oxydoras, 

 + Centyoinochlus, 

 + StegopJiiliis, 



X Cetopsis, 



X Age7ieiosus, 



X + Hoplostermim, 



X + HemiodoiitichtJiys, 



X + Sturisoma, 



X + Hypoptopoma, 



X + Pyrrhitlina, 



X + Psectvogaster, 



+ Otriiiiafe/hi, 

 X + A nod Its, 



+Parodoii, 



+ Hemiodus, 

 X + Anisitsia, 

 X + Nannostomus, 



Anostonms, 



+ Charax, 

 Leporellus, 

 X + HoloshestJies, 

 X + Odontostilbe, 



Cheirodou, 

 X + Aphyocharax, 



+ Heniigvammus, 

 X+ Gasteropelecus, 



CJiakiims, 

 X + Piabuciis, 

 X + Pygopvistis, 



+ Pygocentrus, 



-f Servasalnio, 

 X + Piaractus, 

 X + Metynnis, 



+ My lens, 

 X + Colossoma, 

 X + Mylossoma, 

 X + Charax, 

 X + Roesfes, 

 Roeboides, 

 Cyuopotamits, 

 Sabniints, 

 + Acestrorhynclms, 

 Eigenmannia, 

 Gymnotus, 

 + Gitoii, 

 X yEqnidens, 

 X + Biotodoma, 

 X + Cichlosonia. 



This area is also characterized by positive features, for we have the 

 genera SteindacJiueria, Pogoiiopoiiia, IVertJieinieria, HonipsilichtJiys, Del- 

 titrits, Parotociiiclits, Deiiterodoii, Henocliilus, Harttia, HoUandicJitJiys, 

 Typhlobagrus, Conlurichthys, KrouichtJiys, peculiar to this province. 



In the number of peculiar genera this province differs more from the 

 Amazon than does that across the Andes in Eucador and Peru (see p. 

 312) and if the degree of difference is a criterion, it is an older fauna. 



