298 PATAGONIAN EXPEDITIONS: ZOOLOGY. 



are Pceciliidcs, some of them distinctly northern and some distinctly south- 

 ern, but none of them causing any surprise. 



Farther south, near the tropic on the Atlantic side, is the basin of the 

 Rio Panuco. Nearly half of its fauna, 15 species out of a total of 32, 

 belongs to the northern fauna. Five species are distinctly tropical. In 

 the following list of species from this river the northern forms are marked 

 with an N, the southern with an S and the Mexican with an M, the transi- 

 tion forms with a T. Marine derivatives are marked Me. The Rio Panuco 

 is on the same degree of latitude north of the equator that the Parahyba 

 is south. The Parahyba harbors over 50 species, all of them equatorial ; 

 of the 32 found in the Panuco less than 16 per cent, are equatorial. 



The Panuco System (after Meek). 



N Lepisostetis osseits (Linnaeus). 



N Lepisosteus tristoechus (Bloch & Schneider). 



N Ictabtrus fuycatus (Le Sueur). 



N Ictaluriis pitnctatus (Rafinesque). 



N Ameiuriis austnilis Meek. 



N Ameiurus mexicamis Meek. 



N Carpiodes tuniidits Baird & Girard. 



N Carpiodes labiosiis Meek. 



N Algansea tincella (Cuvier & Valenciennes). 



N HybognatJuis rasconis (Jordan & Snyder). 



N Aztecida mexicnria Meek. 



N Notropis forlonensis Meek. 



S A sty ana X mexicaiuts (Filippi). 



N Dovosoma exile Jordan & Gilbert. 



N Sigualosa mexicana (GUnther). 



N Fimdnlus heteroclitus (Linnaeus). 



T Cyprinodon eximius Girard. 



T Gambiisia affiiiis (Baird & Girard). 



M Goodea toweri Meek. 



M Goodea atripinnis Jordan. 



M Platypoecihis variatiis Meek. 



T Pcecilia latipuuctata Meek. 



T Poecilia sphenops Cuvier &: Valenciennes. 



T Molienesia latipinna Le Sueur. 



