FISHES. 121 



inferior position of the eyes, which are usually below the level of the mouth. The six 

 or eight known species inhabit the rivers of northern Brazil and Surinam. 



According to Dr. Gtinther, " the first appearance of Siluroids is indicated by some 

 fossil remains in tertiary deposits of the highlands of Padang, in Sumatra, where 

 Pseudotropius and JBagarius, types well represented in the living Indian fauna, 

 have been found. Also, in North America, spines referable to cat-fishes have been 

 found in tertiary formations." 



OuDER VI.— SCYPHOPHOEI. 



The small order of Scyphophori is placed by its author, Pi-ofessor Cope, between 

 the Siluridse and the CyprinidsB ; but, according to Professor Gill, its most intimate 

 relations are with the Gymnonoti. The following are the technical characters origi- 

 nally assigned to it : Physostomous fishes, with the " isarietals narrow, distinct from 

 each other and the supra-occipital. Pterotic large, funnel-shaped, enclosing a cham- 

 ber which expands externally, and is covered by a lid-like bone. No symplectic. 

 Opercular bones present. Anterior vertebrae unaltered. No mesopterygium. Basis 

 cranii simple. No interclavicles." 



About fifty-five species of Scyphophori are known, inhabiting the rivers of tropical 

 Africa, where many of them are important as food-fishes. They have an oblong or 

 elongate form, the head naked, the body scaly, the dorsal fin rather long, of soft rays 

 only, the mouth usually small, and the gill openings reduced to a small slit. All of 

 the species possess a rudimentary electric organ on each side of the tail. This is said to 

 be " 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 containing a gelatinous substance." 



Two families are usually recognized in this order ; the MoEMTKiDiB, having the 

 ventral, anal, and caudal fins well developed, and the tail diphycercal; the other, 

 GvMifAECHiD^, with the lower fins all wanting, and the isocercal tail without a caudal 

 fin. Of the latter family, a single species only, Gymnarchus niloticus, is known. 

 This fish reaches a length of six feet, and is remarkable for the cellular structure of 

 its air-bladder, resembling that of Amia and Lepidosteus, and probably similarly used 

 as an imperfect lung. 



Species of Mormyrus found in the Nile were " an object of veneration to the 

 ancient Egyptians, and [its representation] therefore frequently occurs in their emble- 

 matic inscriptions. They abstained from eating it because it was one of the three 

 different kinds of fishes accused of having devoured a member of the body of Osiris, 

 which, therefore, Isis was unable to .recover when she collected the rest of the scattered 

 members of her husband." ( Gilnther.) 



Ojbdek VII. — TELEOCEPHALI. 



The great majority of the true fishes are, in Professor Gill's classification, referred 

 to a single order, which is terme'd by him Teleocephali. This includes the orders of 

 Glanencheli, Hajjlomi, Isospondyli, PlectosiDondyli, Percesoces, Synentognathi, Per- 

 comorphi, and Pharyngognathi of Professor Cope's system, or the orders of [Gymno- 

 noti] Eventognathi, Isospondyli, Haplomi, Synentognathi, and Acanthopteri of the 

 arrangement adopted by Jordan and Gilbert. 



