EXISTING GROUP. 



329 



great masses in the Chako swamps ; their shells being easily crushed by the power- 

 ful teeth of their devourers. 



The African mud-fish (Protopterus annectans), widely spread 

 African Mud-Fish. . . « , • p ,.,.,. 



over the tropical regions of the continent from which it takes its 



name, differs from the last in that the filamentous fins retain a small fringe 



containing rays ; as well as in having six gill-arches, with five intervening clefts, 



while there are three small tentacle-like appendages above the small gill-opening 



on each side. In the Gambia River, where they are very abundant, these fishes 



are in the habit of burying themselves during the dry season, making a kind of 



afkk'an MOD-FISH (J? nat. size). 



nest, in which they pass a period of torpidity. Here they may remain for the 

 greater part of the year, only resuming their normal aquatic life with the return 

 of the wet seasons. Professor W. N, Parker, who received some specimena in the 

 torpid condition, writes that about a hundred individuals were dug out and packed 

 up in crates still enclosed in the clods of mud. On arrival in Europe the clods 

 were opened, and the fishes placed in a tank in a hothouse. Tin' statement of tin- 

 natives that the species grows to the almost incredible length of 6 feel suggests 

 that it must be a very long-lived creature. From tin' above-mentioned specimens 

 it was found that these mud-fishes grow very rapidly, have greal vitality, and. 

 although able to sustain fasts, are exc dingly voracious, devouring all the snails, 



