SÜB-CLASS VI 



TELEOSTEI 



I 



North America, but do not occur in South America. 



fossil species, all from fresh- 



water formations, belong 



to the existing genera 



Leuciscus, Klein (Fig. 177), 



Tinea, Gobio, Barbus, Cuv., 



Bhodeus, Aspius, Ag. (Fig. 



178), Cyprinus, Cobitis 



(Artedi), Linn., Nemachilus, 



Cuv., Thynnichthys, Bleeker, 



etc. The only extinct 



genera, such as Amyzon, 



DiastichuS, Oligobelus, Cope, Scales of Leudscus oeningensls, Ag. 

 r,^A ^^-V.^«^ ^«^ 1 1 Upper Miocene ; Oeningen, Baden, 

 and Others, are closely Enlarged (after Winkler). 



related to existing forms. 



101 



Most of the known 



Fio. 177. 



Pharyngeal bones and 

 teeth of Aspius rapax, Ag. 

 Recent (after Heckel and 

 Kner). 



Family 18. Siluridae. Cat-fishes. 



Scaleless fishes, naked or armoured with bony plates. Premaxilla exduding 

 maxilla from upper riiargin of mouth, the rudimentary maxilla usually supporting a 

 barbel. Suboperculum absent. Infraclavicular plates present. Anterior pedoral fin 

 ray usually a strong bony spine. Anterior vertebrae and air bladder as in Cyprinidae. 

 Eocene to Recent. 



The Siluroids form a very numerous family of freshwater fishes, ranging 

 over all temperate and tropical regions, and a few sometimes passing into the 

 sea round the coasts. Fossil remains are rare, and represent fishes closely 

 resembling those still surviving. The oldest known fragment is a portion of 

 head (Bucklandium diluvii, König) from the London Clay of Sheppey. Typical 

 remains of Arius occur in the Middle and Upper Eocene of the Hampshire 

 Basin and Belgium. Other genera are recorded from the Eocene of Wyoming, 

 U.S.A. (Bhineastes, Cope), the Lower Pliocene of the Siwalik Hills, India, 

 and a Tertiary Lignite near Padang, Sumatra. 



Family 19. Muraenidae. Eels. 



Body much elongated, cylindrical or ribbon-shaped. Premaxillae fused with 

 ethmoid and vomer ; upper jaw formed laterally by the toothed maxilla. Dorsal fin 

 much extended, often meeting the anal round the tail. Pect oral arch not suspended from 

 the cranium ; pelvic fins wanting, Skin naked, or with small, rudimentary, cycloid 

 scales. Upper Cretaceous to Recent. 



Urenchelys, Sm. Woodw. With separate caudal fin. Upper Cretaceous ; 

 Sahel Alma, Lebanon, and English Chalk. 



Eomyrus, Storms. Middle Eocene ; Belgium. 



Species of existing genera from marine Upper Eocene, Monte Bolca, and 

 freshwater Upper Miocene, Oeningen. 



Order 2. PHYSOCLYSTI. GiU. 



Air bladder, when present, not connected by a tube with the Oesophagus in the 

 adult (except in certain Berycidae). Gills pectinate. Pelvic fins usually far forwards ; 

 fin rays articulated or spinous. Scales, when present, cycloid or ctenoid. 



