March, 1914. List of Fishes of Costa Rica — Meek. hi 



scales; bones of the lower jaw firmly united; teeth conical or 

 villiform. Alfaro. 



aa. Lower edge of caudal peduncle rounded, or obtuse, with a median 

 series of scales. 



b. Ventral fins similar in both sexes; first produced ray of anal fin 

 of male without long processes or appendages. 



c. Anal fin of male short, ending in a small retrorse hook formed by 

 second and third produced rays; teeth conical or villiform, not 

 movable. Brachyrhaphus. 



cc. Anal fin of male ending in a more or less distinct antrorse hook; 

 the anterior branch of the second produced ray curved forward. 



d. Mouth moderate, with distinct lateral cleft; teeth conical or 

 viliform, not movable. 



e. Dorsal rays 7 to 1 2 ; origin of dorsal behind that of anal ; extremity 

 of anal fin of male supported equally by third and anterior 

 branch of second produced rays. Priapichthys . 



ee. Dorsal rays 11 to 17; origin of dorsal in advance of that of anal; 

 extremity of male anal fin a strong hook and formed by the 

 unsegmented end of the anterior branch of the second ray. 



Pseudoxiphophorus, 



dd. Mouth small, transverse; teeth oar-shaped, movable; extremity 



of anal fin of male supported equally by first and anterior branch 



of second produced rays; first ray not serrated. Poeciliopsis. 



bb. Ventral fins enlarged in the males, the second ray longest; first 



prolonged anal ray bearing a small antrorse spine at or near its 



end; last bearing a pair of processes directed outwards and 



towards the' base of the fin. Mollienisia, 



The following is a key to the species PaecUimcB listed here and is 



based mostly on characters of the females: 



a. Dentary bones firmly united; teeth not movable; alimentary 

 canal shorter than the body. 



b. Lower edge of caudal peduncle sharp, without a median series of 

 scales. Alfaro cultratum. 



bb. Lower edge of caudal peduncle rounded or obtuse, with a median 

 row of scales. 



c. Origin of dorsal well behind that of anal. 



d. No caudal spot; middle half of sides with 5 to 8 narrow vertical 

 lines; D. 7. A. 9 or 10. Priapichthys turrubarensis. 



dd. A prominent caudal spot; no dark bars on sides; D. 7 or 8; A. 

 8 or 9. Priapichthys parismina. 



