180 MEMOIRS OF THE CARNEGIE MUSEUM. 
jured anal. The entire piece was normally scaled and marked with the typical 
bands of pale yellow and dark blue (compare with Fig. 22, the normal tail). It 
differed chiefly in being a little smaller than the uninjured part of the body, which 
gave the fish a constricted appearance along the line of injury. 
Fic. 20. Regenerated Tail. Gymnotus carapo (Linnzus), Santarem, Brazil. 
The third case was quite different. This fish, a specimen one hundred and 
thirty millimeters long, from Aqua Quente, Paraguay, had received an injury 
parallel to the lateral line. The caudal appendage and caudal portion of the 
body were split for a distance of thirty-five millimeters. Both pieces had rounded 
themselves out so that there were two well-formed caudal appendages, each longer 
than the normal. The ventral tail has an anal fin regularly attached except for a 
slight fold (see Fig. 21). 
Via. 21. Split Tail. Gymnotus carapo (Linnzeus), Aqua Quente, Paraguay. 
Fic. 22. Normal Tail. Gymnotus carapo (Linneeus), Holmia, British Guiana. 
Taken collectively these regenerations show G. carapo capable of rather 
complete regeneration of injuries in the caudal region. Caudal appendage, muscle 
scales, color markings, and anal fin were all restored. It, of course, could not be 
determined absolutely whether these injuries had been received when the fishes 
were much smaller and the regenerated parts, after some fraction of the part re- 
moved had been restored, had grown with the rest of the fish, or whether the regen- 
erations were the results of recent injuries, and really represent the amount of tissue 
lost. The appearances all favor the view that the injuries were recent. The 
