I02 Field Museum of Natural History — Zoology, Vol. X. 



While collecting fishes in Costa Rica I was much aided in way of 

 transportation by the United Fruit Company. I also received many 

 courtesies from its agents at Limon, Zent, Victoria, and San Jose, also 

 from Mr. Zeledon at Parismina. 



Prof. Tristan of San Jose accompanied me to Orotina and the Rio 

 Turribales; Dr. Alfaro assisted me in collecting near San Jose. He also 

 arranged for me transportation to Orotino and return, besides giving 

 me the ser^nces of his assistant, Mr. Jesus Maria Moran, while I was 

 on the western slope of Costa Rica. Dr. Alfaro permitted me to 

 examine all of the fresh-water fishes from Costa Rica which he had 

 collected from time to time in the past. 



The following is a list of localities where collections were made b\^ 

 me in Costa Rica in April, 191 2: 



La Junta, small stream near station April 



Guapilis, Rio Guapilis 



Virginia, Rio Virginia 



Parismina, Rio Parismina 



Zent, Rio Zent and Rio Cuba 



La Victoria, Rio Zent and tributaries 



Zent, Rio Zent 



San Jose, Rio Maria Aguilar 



San Jose, Rio Torres 



Orotina, Rio Machuca 



" Rio Turrubales 



" Rio Grande 



Jesus Maria, Rio Jesus Maria and Rio Machuca . 

 San Jose, Rio Tiribi 



8 



9 

 10 

 12 

 13 

 15 

 iS 



IQ 

 20 

 21 

 22 



26 



Costa Rica is a well watered country. The sides of the tall vol- 

 canoes are furrowed by many small streams which unite, forming near 

 their bases large rivers. The Reventazon from its source to be\'ond 

 La Junta is a raging torrent ; the same is true of the Rio Tarcoles oppo- 

 site on the Pacific side. The smaller streams visited by me on the 

 north slope of Volcano Turialba flowed with considerable current over 

 rocky or gravelly bottoms. There were only occasional stretches where 

 the bottom was smooth enough to permit successful seining. The 

 Rio Zent had much less current with a gravelly and sandy bottom. 

 In the foot hills above La Victoria there were cascades and rapids. 

 The Rio Cuba flowed, where visited, through a marshy region in a 

 deep channel. In all of these streams the water was clear. 



On the Pacific slope the streams are much the same as those on the 



