128 PROCEEDINGS OF THE NATIONAL MUSEUM vol. lie 



shown rather good intuitition in their interpretation of the relation- 

 ships of these fishes; however, others have not been so fortunate in 

 their interpretation and these fishes have been shifted about in the 

 classification of characids until it is very difficult to obtain from the 

 literature a concept of their affinities. 



Investigation of Nannostomus, Poecilobrycon, and their relatives 

 led to comparison of two widely divergent characid subfamilies, the 

 Characinae, treated by Weitzman (1962), and the Lebiasininae, 

 treated here. In addition the Erythrininae, another divergent 

 subfamily of the Characidae, are compared with the Lebiasininae 

 because these two groups of characids often have been thought to 

 belong to a single group. Although the work began as an effort to 

 determine the relationships of Nannostomus and Poecilobrycon, its 

 most important result concerns the relationships of the subfamilies 

 Lebiasininae and Erythrininae. 



The morphological data obtained in the present study has resulted 

 in the following classification, the names given below being used 

 throughout this paper (see pages 148 to 152 for a full treatment of the 

 classification) : 



Subfamily Lebiasininae 



Tribe Lebiasinini 

 Tribe Pyrrhulinini 



Subtribe Pyrrhulinina 



Subtribe Nannostomina 

 Subfamily Erythrininae 



For the loan of specimens, I am indebted to Dr. George S. Myers 

 of Stanford University, Mr. W. I. Follett of the California Academy 

 of Sciences, Dr. James Bohlke of the Academy of Natural Sciences 

 of Philadelphia, and Mr. Loren P. Woods of the Chicago Natiu-al 

 History Museum. I am indebted especially to Dr. George S. Myers 

 for critically reading much of the manuscript and offering aid and 

 advice during most of its preparation. In addition, the following 

 persons have read the manuscript at various stages, all providing very 

 useful help: Mrs. LiUian Dempster of the California Academy of 

 Sciences, Drs. Myra Keen and Warren Freihofer of Stanford Univer- 

 sity, and Drs. Leonard P. Schultz, Kobert H. Gibbs, Jr., and Victor 

 G. Springer of the U.S. National Museum. 



The work was done at the Department of Biological Sciences, 

 Division of Systematic Biology of Stanford University, at the Depart- 

 ment of Anatomy, Stanford University School of Medicine, and at 

 the U.S. National Museum, Smithsonian Institution. 



