SOURCES OF THE MATERIAL. 5 



or which (Alestes and Brachyalestes) are geographically extra-limital, there 

 remain: — Tetragonopterus, with thirty-two species; Scissor, with one species; 

 Pseudochalceus, with one species; Bryconops, with two species; Creagrutus, 

 with one species; making a total of five genera, with thirty-seven species. 



Of the Iguanodectinae, which were included in Gunther's Tetragonopterina, 

 he recorded two species belonging to the genus Piabuca. 



He recorded four species of Corynopoma and placed them in his Erythrinina. 

 They are the Slevardia albipinnis considered below in the discussion of the new 

 subfamily, Glandulocaudinae. 



In the last general review of Gunther, there were a grand total of seven 

 genera and forty-three species, as compared with the fifty-two genera and over 

 three hundred species, known today. 



SOURCES OF THE MATERIAL. 



The Nathaniel Thayer Brazilian Expedition. 



In January 1807, Karolina, Archduchess of Austria, was married to the 

 Crown Prince of Brazil. In the retinue accompanying the young couple to Brazil 

 went Johann Natterer of Wien. Natterer remained in Brazil for eighteen years 

 and collected extensively from Rio de Janeiro to Cuyaba, thence down the 

 Madeira to the Amazon and up the Rio Negro and Rio Branco. Taking advan- 

 tage of the opportunity, the King of Bavaria sent two naturalists, Johann Bap- 

 tist von Spix and Carl Friedrich von Martius with the bridal party. They 

 also collected natural history specimens. The routes of travel of Natterer and 

 of Spix and Martius are shown on Plate 1. 



The fishes collected by Natterer were described by Heckel, Kner, and 

 Steindachner. Those collected by Spix and Martius were being described by 

 Spix when he died. Louis Agassiz, then a student at the University of Munich, 

 was selected to complete the work of Spix. Agassiz's work resulted in a sumptu- 

 ous folio, and a desire to personally inspect the fauna of Brazil, a desire fulfilled 

 forty years later. In 1865, the generosity of Mr. Nathaniel Thayer made it 

 possible for Agassiz to undertake his journey to Brazil. 



. The assistants of the Thayer Expedition were James Burkhardt, artist, 

 J. G. Anthony, conchologist, C. F. Hartt, and Orestes St. John, geologists, J. A. 

 Allen, ornithologist, and George Sceva, preparator. Besides these assistants 



