CHAPTER X 

 THE SCYPHOPHORI, HAPLOMI, AND XENOMI 



'RDER Scyphophori. The Scyphophori ((TKV</)OS, cup; 

 finpeoo, to bear) constitutes a small order which lies 

 apparently between the Gymnonoti and the Isospondyli. 

 Boulenger unites it with the Isospondyli. The species, about 

 seventy-five in number, inhabit the rivers of Africa, where 

 they are important as food-fishes. In all there is a deep 

 cavity on each side of the cranium covered by a thin bony 

 plate, the supertemporal bone. There is no symplectic bone, 

 and the subopercle is very small or concealed. The gill-openings 

 are narrow and there are no pharyngeal teeth. The air-bladder 

 connects with the ear, but not apparently in the same way as 

 with the Ostariophysan fishes, to which, however, the Scypho- 

 phori are most nearly related. In all the Scyphophori the body 

 is oblong, covered with cycloid scales, the head is naked, there 

 are no barbels, and the small mouth is at the end of a long 

 snout. All the species possess a peculiar organ on the tail, 

 which with reference to a similar structure in Torpedo and 

 Electrophorus is held to be a degenerate electric organ. Accord- 

 ing to Giinther, "it is without electric functions, but evidently 

 representing a transitional condition from muscular substance 

 to an electric organ. It is an oblong capsule divided into 

 numerous compartments by vertical transverse septa and con- 

 taining a gelatinous substance." 



The Mormyridae. There are two families of Scyphophori. 

 The MormyridcB have the ordinary fins and tail of fishes and the 

 Gymnarchida are eel-like, with ventrals, anal and caudal wanting. 

 Gymnarchus miloticus of the Nile reaches a length of six feet, 

 and it is remarkable as retaining the cellular structure of the 

 air-bladder as seen in the garpike and bowfin. It doubtless 

 serves as an imperfect lung. 



iSS 



