4 THE AMERICAN CHARACIDAE. 



Still later (December 1911-April 1912) I made extensive collections in 

 Colombia; and in the early part of 1913 two of my students, Mr. Arthur M. 

 Henn and Mr. Charles Wilson, gathered many fishes in the streams of western 

 Colombia. Mr. Henn remained in South America till 1914 and extended the 

 explorations to western Ecuador. Smaller collections were made by Miss Lola 

 Vance in the streams about Tarma, Peru, and by Dr. Ellis and Dr. William 

 Tucker in British Guiana. The collections of the Yale-National Geographic 

 Society Expedition to the Urubamba River have also been available in the 

 preparation of this monograph. 



These different collections admirably supplement each other. They are 

 the most extensive collections that have ever been brought together from South 

 America. In the number of specimens at my disposal they far exceed the com- 

 bined collections recorded in all other museums of the world. 



The number of American species of Characins exceeds six hundred; and as 

 they offer some of the best material to demonstrate several facts of evolution 

 it is hoped to illustrate the species quite thoroughly. To provide for the illus- 

 trations of the Tetragonopterinae I am indebted to the Trustees of the Eliza- 

 beth Thompson Science Fund for an appropriation of $250.00, and to the 

 Trustees of the Bache Fund for a similar amount. The Carnegie Museum and 

 Mr. H. W. Fowler have granted the reproduction of a number of figures. 



The portion of the monograph dealing with Hemigrammus, Hyphessobrycon, 

 and Hasemania was prepared with the collaboration of Marion Lee Durbin, now 

 Marion Durbin Ellis. 



This Memoir deals with the Tetragonopterinae, 1 Rhoadsinae, Glandulo- 

 caudinae, Iguanodectinae, Stethaprioninae, and Stichanodontinae. All of the 

 then known species of these subfamilies, except the species of Stevardia, were 

 included by Gunther (Cat. fishes Brit. Mus., 1864, 5) in the Tetragonopterinae. 

 There are recognized in this Memoir fifty-two genera, and three hundred and 

 twelve species. Over half of these were described during the course of the prepa- 

 ration of the Monograph. 



The subfamily Tetragonopterinae, at present the dominant group of tropi- 

 cal American fishes, was defined by Gunther (loc. cit.) to include Piabucina, 

 Alestes, Brachyalestes, Chirodon, Chalceus, Brycon, Chalcinopsis, Chalcinus, 

 Gasteropelecus, Piabuca, and Agoniates, besides the genera listed below. Elimi- 

 nating these genera, which are now relegated to various separate subfamilies 



1 The portion of the Monograph dealing with the Cheirodontinae appeared recently in the Memoirs 

 Carnegie Museum, 1916, 7, p. 1-99, pi. 1-17. 



