Marcu, 1914. List or Fisnes or Costa Rica — MEEK. 105 
Family Cyprinide. 
Carassius auratus (Linnzus). 
Introduced species, which has escaped from aquaria. 
Pacific side (1), 124 mm.; San José (in captivity) (1), 112 mm. 
Family Characide. 3 
Astyanax zneus costaricensis var. nov. 
Astyanax erstedii Meek, Pub. Field Mus., Zool. Ser., vir, 1907, 145 
_(Turrialba). 
Tetragonopterus eneus Regan, Ann. & Mag. Nat. Hist., 1908, 455, 
part (Rio Iroquois, Costa Rica). 
Astyanax @neus (Ginther) is very variable and when studied in 
more detail will, no doubt, be found to comprise a number of fairly well 
marked varieties. Specimens examined by me from both sides of 
Guatemala appear to be the same, Astyanax a. micropthalmus (Ginther). 
In these the inner premaxillary teeth are 5-5, though occasionally 
these are 4-5. The maxillary teeth are 2-2, but these are sometimes 
I-2 or 2-3. The anal rays range from 26 to 30. In form those from 
any one locality vary greatly, some being slender, others comparatively 
deep. Specimens from Lake Managua, Nicaragua, resemble those 
from Guatemala, except that the snout averages a little shorter and 
slightly blunter, the inner row of premaxillary teeth is 5-5, except 
occasionally 4-5. There are also a few more teeth on the maxillary; 
these are usually 2-3, but are occasionally 3-3 or 3-4. The anal rays 
average a little less, ranging from 25 to 29. This form is the Astyanax 
erstedii (Kroyer) and the Astyanax nicaraguensis Eigenmann and 
Ogle. 
In Costa Rica there are two well-marked varieties or species. Those 
from the Atlantic slope resemble the preceding forms, in that the inner 
premaxillary teeth are 5-5 (occasionally 4-4 or 4-5). The maxillary 
teeth are 2-2; these occasionally vary from o to 3; the anal rays vary 
from 28 to 31 (Astyanax a. costaricensis Meek). 
Specimens from the west side of Costa Rica have the inner maxillary 
teeth 4-4, occasionally 4-5; the anal rays vary from 26 to 31. The 
form from the west side of Costa Rica differs rather more from the 
other forms than they do from each other (Astyanax albeolus Eigen- 
mann). 
