110 MEMOIRS OF THE CARNEGIE MUSEUM. 



frequent injur}' and subsequent regeneration of the caudal region of the members 

 of this family; and (3) the mode of locomotion. 



These questions and others made a study of the living fishes very desirable 

 before the comiDlotion of this monograph. This matter was laid before Mr. Jake 

 Gimbel of Vincennes, Indiana, who generously agreed to finance an expedition to 

 British Guiana. In August, 1910, the writer, with Mr. William Tucker, a volunteer 

 assistant, sailed via the Quebec Line for Georgetown, British Guiana. Studies of 

 the living Gymnotidce were made in the trenches in and about Georgetown. A trip 

 was made to liubabu Creek, the first inland fresh-water creek emptying into the 

 Demerara River. The Demerara is still brackish at the mouth of Hubabu Creek. 

 Two excursions were also made to Gluck Island in the Essequibo River opposite 

 Rockstone. This island is about one hundred miles from the coast. Collections 

 were also made in the harbor and on the mud-flats at Georgetown. A new Gym- 

 notid, Porotergus gimbeli, was added from Hubabu Creek. 



During the spring of 1910, Mr. Bertoni of Puerto Bertoni, Paraguay, sent 

 Indiana University a small collection of fishes from the upper Parana River. 

 Among these was a specimen of the new species Gymnorhamphichthys hypodomus. 



The several collections mentioned, as well as the material in the Indiana 

 University Museum, offered an excellent opportunity for a revision of this family. 

 Twenty-two of the twenty-seven known species are in the collections examined, 

 all of the twenty-two being in the collections of the Carnegie Museum. I wish to 

 thank Dr. C. H. Eigenmann for his many helpful suggestions and criticisms. I am 

 deeply indebted to Mr. Jake Gimbel for his generous support of the trip to Guiana, 

 without which certain sections of this monograph could not have been written. 

 I am also under obligations to the Quebec Steamship Line of Quebec and London, 

 and Sproston's Limited of Georgetown, for their grants of transportation, and to 

 Mr. Bernard Conrad of Georgetown, who aided me in many ways during my stay 

 in Guiana. 



History op the Literature of the Gymnotid^. 



The first scientific record of any species of this family is that of Georg Marcgraf 

 (1648), who described as "carapo" the species now known as Gymnotus carapo. 

 His fish came from Brazil. The name Gymnotus carapo was given to this species 

 by Artedi in 1738. He placed it under "Ordo I, Malacopterygii," with the simple 

 description, " Membrana branchiostega ossiculis quinque. Pinna dorsalis nulla" 

 (Genera, p. 25, and Synonymia, p. 43). Linnaeus under his Apodes listed Gymnotus 

 carapo and asiaticus in the tenth edition, and Gymnotus carapo, electricus, albifrons, 

 roslratus, and asiaticus in the twelfth edition of the Systema Naturce. 



The beginning of real interest in this group of fishes was about forty years 

 before the appearance of the twelfth edition. In 1729 Richter published the first 

 scientific article on the electric eel. This stimulated the study of the Gymnotido'.. 

 As a result, scarcely a decade has passed since Richter's paper appeared without 

 the publication of some contribution bearing upon the electric eel or its relatives. 



