312 PATAGONIAN EXPEDITIONS: ZOOLOGY. 



sidering it two things may be borne in mind : i, that the province, while 

 very long, is very narrow and contains no large river system, which is so 

 necessary to develop or harbor a diverse fauna. The sources of the 

 Paute, a tributary of the Maranon are only 60 km. from the bay of Guay- 

 aquil. In North America the large Colorado, Sacramento or Columbia 

 basins of the Pacific slope contain fewer species of fishes than the un- 

 known Beanblossom creek of the Mississippi basin : 2, that no river has 

 been thoroughly explored and some of the principal ones, the San Juan 

 and Patia for instance, not at all. 



With very few exceptions, the species of this province belong to genera 

 with a very wide distribution ; on the Atlantic slope, all but one of these 

 genera reach as far north as the Magdalena or Panama. Few of the species 

 would have occasioned surprise if they had been discovered at Manaos. 

 There are remarkably few peculiar genera, which indicates a compara- 

 tively recent separation from the Atlantic slope fauna. The species 

 recorded from this province are listed below and marked "*" for species 

 peculiar, "**" genus peculiar, "/" species found also in the Chagres or 

 Magdalena, "Me" marine. Most of the species are recorded from Ecua- 

 dor, few are found in Peru, and Colombia has not been explored. 

 / Rhamdia cinerascens (Gunther) : Rio Daule ; Rio Peripa; Guayaquil and 



Esmeraldas ; Chagres. 

 / Rlianidia wagneri (Gunther) : Atlantic and Pacific slope of Panama ; 



Mamoni near Chepo. 

 / Pimelodits clarias (Bloch) : Rio Bayano — eastern slope to Buenos Aires. 

 / Pinielodella iiiodesfa (Gunther) : Eastern Panama ; Esmeraldas. 



* Pinielodella elongata (Gunther). 



* Pinielodella grisea Regan : Durango ; Sapayo and Vaqueria Rivers, in 



northwest Ecuador. 



* Pinielodella yuncensis Steindachner : Pacasmayo. 



** Cetopsogiton occidentalis (Steindachner) : Guayaquil. 



Species of Pygidinm, Arges, Cyclopimn and Chcstostomus considered 

 under the Andean Region may descend into this province. 



* Pygidinm pnuctnlatuni (Cuvier & Valenciennes) : Callao. 



* Pygidinm pardus (Cope) : Jequitepeque ; Callao Bay. 



* Plecostomiis spinosissimus Steindachner : Guayaquil ; Rio Vinces ; Rio 



Daule. 



* Plecostomns festce Boulenger: Rio Vinces; Rio Peripa. 



