2 1 8 CYPEINIDJE.— SILUKID.E. 



The Gold-fish {Cf/pn'nus auratus, L.), a native of Asia, has been 

 introduced and has become acclimatized in North-west and South Africa, 

 in Madagascar, and in Mauritius. It is easily distinguished from all 

 the indigenous African Cyprinids by its long dorsal fin with at least 

 15 branched rays, and by the last simple ray of both dorsal and anal 

 being serrated. When in a wild state the fish loses the bright coloration 

 whence its specific name is derived. 



Fam. 3. SILURIU.^. 



Mouth non-protractile, bordered by the piiemaxilliiries nnd the 

 maxillaries, or by the pniemaxillaries only, the maxillaries being often 

 rudimentary and supporting the base of a barbel ; jaws usually toothed. 

 Parietal bones usually confluent with the supraoccipital ; symplectic and 

 suboperculum absent. Pharyngeal bones normal, with small teeth. 

 Some or all of the ribs attached to the lower surface of long parapopln ses ; 

 cpipleurals absent. Pectoral fins inserted very low down, folding like 

 the ventrals, often armed, like the dorsal, with a strong bony spine. 

 Body naked or with bony plates. An adipose dorsal fin often present. 

 One to four pairs of barbels. 



Fresh-waters of all temperate and tropical parts of the world and 

 coasts within the tropics and round South Africa. 



Synopsis of the Genera. 



I. Clariin^. — Dorsal and anal fins very long, without spine; gill-ineinl)ranes 

 free from the isthmus ; air-bhidJer small, bilobed, disposed transversely and 

 partially enclosed in a bony sheath. 

 A. Dorsal fin single, formed entirely of articulated rays. 



1. Eye with a free border ; pectoral and vential fins well developed. 

 Sides of head protected by bony shields . . 1. Clarias, Gron., p. 22i. 

 Sides of head naked, only the postorbital shield 



being present 2. ^{lUtheiichel/j,^, ll\gv., [k '2(j6. 



2. Eye without free border ; sides of head naktul. 

 Postorbital shield present ; ])ectoral fins well 



developed, ventrals small .'». ('Idrialldlx'n, l^'g'"*- !'• -*''^* 



Postorbital shield absent ; [)ectoral and \('ntral 



fins very small -1. (iri/)nnall((I>ex, (xtlir., p. 270. 



Poslorbilal shield absent : pectoral Hn< nidi- 



mentary or ab-ent. Ncntral- al»eiit, . . "). < limniaHahei'. (ithr.. p. 271- 



