THE GYMNOTID EELS OF TROPICAL AMERICA. 



179 



appendage. The following table gives the data for these, 

 from which they came are in British Guiana. 



Gymnotus carapo. 



All three of the localities 



The other three cases proved more interesting. 



One specimen, body length estimated 125 mm., from the Rio Coite, Eastern 

 Brazil, had lost the entire caudal appendage and about twenty millimeters of the 

 caudal portion of the body. It had been lost by an irregular injury which ran at 

 right angles to the back. The regeneration had been most rapid in the region of 

 the backbone. The new tissue at this point being six millimeters long and bearing 

 a new caudal appendage nearly two millimeters in length. There had been scarcely 

 any repair to the extreme ventral edge of the injury in the region of the anal fin. 

 The entire piece of regeneration tissue was thus roughly triangular. It bore 

 along its ventral margin several very tiny fin-rays, not over half a millimeter long, 

 and its maximum thickness was nearly two millimeters, only about one-half that 

 of the uninjured body, just in front of it. The dorsal portion of the new tail was 

 scaled over most of "its basal half. The regenerated portion was uniformly pale 

 yellow in color and without markings. Fig. 19 is an outline drawing of this tail. 



Fig. 19. Regenerated Tail. Gymnotus carapo (Linnaaus), Rio Coite. 



Another individual three hundred milUmeters long, from the Amazon at Santarem, 

 Brazil, had received nearly the same kind of injury, differing, however, in that 

 the regeneration was much farther advanced. (See Fig. 20.) Nearly eighty 

 millimeters of the body, and the entire caudal appendage, had been lost by a rather 

 straight inj ury across the body. Of this sixty-five millimeters had been regenerated. 

 The new tail bears a caudal appendage eight millimeters long and a small well 

 developed fin. The latter is completely, although irregularly, joined to the unin- 



