Evermann and Goldshorough — Fishes from Canal Zone. 97 



out of existence, and even those which are not exterminated 

 will have their geographic distribution seriously affected and 

 their habits more or less changed. It is a source of great regret 

 to biologists that the Government has not appreciated the 

 necessity for a thorough biological survey of the Canal Zone 

 before the completion of the canal. It is not yet too late to 

 make such a survey, but it must be made before the canal is 

 completed; else problems which can now be solved will then 

 remain forever unsolved. 



The collection of fishes upon which this paper is based, 

 although small, is nevertheless of considerable importance, and 

 it is highly desirable that the facts gained from their study 

 be put on record. 



Family CHARACINID.E. 



THE CHARACINS 



1. Astyanax aeneus (Giinther). 



Seven specimens, 40 to 47 mm. long, from Tabernilla, January 15. 

 Ten specimens, 65 to 105 mm. long, from Rio Boqueron. 



2. Astyanax fischeri Steindachner. 



Twenty-five specimens, 35 to 63 mm. long, from Tabernilla, July 24. 



Three specimens, 55 to 63 mm. long, from a small pool at Paraiso, Feb- 

 ruary 1. 



These two species are doubtfully distinct. A. fischeri seems to differ, 

 however, from A. xneus in the slightly larger eye, slightly greater depth, 

 and in the coloration, the former always having a vertical black humeral 

 spot bordered on each side by silvery, and a black caudal spot which 

 does not extend on the caudal rays. 



A comparison of our specimens of A. seneus with 2 examples of A. 

 macrophthalrmis from the Rio Tonto, Mexico, kindly sent us by Mr. C. 

 Tate Regan, shows them to be distinct, as evidenced by the slightly larger 

 eye and higher dorsal fin of A. viacrophthalmus . "We are unable to ob- 

 serve any differences in the anal fin. 



For purposes of comparison we give comparative measurements of a 

 series of specimens of each of the species, A. fischeri, A. wneus, and A. 

 viacrophthalmus. 



