xliv FIELD COLUMBIAN MUSEUM ZOOLOGY, VOL. V. 

 RIO PAPALOAPAM SYSTEM. 



The Rio Papaloapam and its tributaries drain nearly all of the 

 eastern slope of Mexico between the Rio Blanco and the Isthmus of 

 Tehuantepec. Owing to the abundance of rainfall in this region this 

 river and its principal tributaries are much larger than their drainage 

 area would indicate. 



The largest bridge in the republic crosses the Papaloapam at El 

 Hule. The portion of the bridge which crosses the main channel is 

 1,100 feet in length. Much of this drainage area is a dense jungle of 

 palms, various other species of trees, shrubs, and vines. 



The following is a list of the known fishes from this river system; 

 all except three* properly belong to the tropical fauna. 



Galeichthys aguadulce Meek: Perez. 



Rhamdia oazacae Meek: Cuicatlan; Motzorongo; El Hule; Obispo; Perez. 



Rhamdia brachyptera (Cope) : Motzorongo. 



*Carpiodes meridionalis (Giinther) : Perez. 



Tetragonopterus mexicanus Filippi: Cuicatlan; Venta Salada. 



Tetragonopterus aeneus Gunther: Motzorongo; Refugio; El Hule; Obispo; Perez; 

 San Juan Evangelista. 



Hemigrammus compressus Meek: El Hule; Obispo. 



*Dorosoma anale Meek: El Hule; Perez; San Juan Evangelista. 



*Dorosoma exile Jordan & Gilbert: Cademaco. 



Signalosa mexicana (Gunther): Obispo; El Hule; Perez. 



Cynodonichthys tenuis Meek: El Hule. 



Pseudoxiphophorus bimaculatus (Heckel) : Motzorongo; El Hule; Obispo; Perez. 



Gambusia bonita Meek: Motzorongo; Refugio. 



Paragambusia nicaraguensis (Gunther): El Hule; Obispo; Perez. 



Belonesox belizanus Kner: El Hule; Obispo; Perez. 



Platypcecilus maculatus Gunther: El Hule; Obispo; Perez. 



Heterandria lutzi Meek: Cuicatlan; Venta Salada; El Hule; Perez; Motzorongo. 



Poecilia sphenops Cuvier & Valenciennes: El Hule; Obispo; Perez; San Juan 

 Evangelista. 



Xiphophorus helleri Heckel: Motzorongo; Refugio; El Hule; Obispo. 



Tylosurus marinus (Walbaum) : Perez. 



Menidia lisa Meek: Refugio; El Hule. 



Agonostomus monticola (Bancroft): Cuicatlan; Motzorongo. 



Centropomus mexicanus Bocourt: El Hule; Perez. 



Pomadasys starri Meek: Perez. 



Pomadasys templei Meek: Perez. 



Cichlasoma salvini (Gunther): Motzorongo; Refugio; El Hule; Obispo; Perez. 



Cichlasoma hedricki Meek: El Hule; Obispo; Perez. 



Cichlasoma par ma (Gunther): Obispo; Perez. 



Cichlasoma melanurum (Gunther): Cuicatlan; Motzorongo; Obispo; Perez. 



Cichlasoma eigenmanni Meek: Venta Salada. 



Cichlasoma nebulifer (Gunther) : San Juan Evangelista. 



Thorichthys helleri (Steindachner) : El Hule; Obispo; Perez; San Juan Evan- 

 gelista. 



Thorichthys ellioti Meek: Motzorongo. 



