ORDER TELEOSTEI. IOOI 



now confined to India, is represented in the Miocene of CEningen 

 and Puy-de-D6me ; the Oriental genera Amblypharyngodon and 

 Thynichthys occur in the Eocene of Sumatra, while the names 

 Cychtrus, Hexapsephus, and Mylocyprinus have been applied to 

 North American Tertiary forms, which are probably more or less 

 closely related to those now inhabiting the same region. 



Family Scopelid^e. — The Scopeloids are marine fishes allied to 

 the Carps (with which they agree in the structure of the jaws), in 

 which the body may be naked, and there are neither barbels nor 

 swim-bladder. They are represented in past epochs by Hemisaurida, 

 of the Cretaceous of Istria, which is allied to the living Saurus, and 

 Parascopelus and Anaptems from the Miocene of Sicily, of which 

 the latter is related to Paralepis now found in the same region. 



Family Silurid.e:. — The Siluroids or Cat-fishes form a large 

 family of freshwater fishes of not less importance than the Carps, 

 inhabiting all temperate and tropical regions, and in some cases 

 entering the sea. The skin is either naked or covered with bony 

 scutes ; there are always barbels, which frequently have a bony axis ; 

 the margin of the upper jaw is formed by the premaxillae ; there 

 is no subopercular ; and there may or may not be an adipose fin. 

 The skull of the Siluroids is often remarkable for the great develop- 

 ment of the supraoccipital (fig. 938), and the presence of dermal 

 ossifications in the region of the neck, which spread over the nape, 

 and articulate with the bones of the secondary pectoral girdle. The 

 first and second interspinous bones of the neck frequently also 

 develop a large bony buckler, behind which the long dorsal spine 

 articulates by means of a ring with the first interspinal ; and this 

 spine can be fixed in an upright position by a curious mechanism 

 connected with the second interspinal. The " helmet " of the nape 

 may be continuous with the " buckler," and these bones, together 

 with those of the cranium proper, are frequently ornamented with a 

 granular sculpture. The pectoral fins frequently carry a spine as 

 large as that of the dorsal. The pharyngeal teeth are generally 

 knob-like. 



From many points in which the Siluroids resemble the Placoder- 

 matous Ganoids, Professor Huxley has suggested that we may re- 

 gard the latter as nearly related to the ancestors of the existing 

 family. Siluroids are not definitely known before the Tertiary, 

 although it has been suggested that Te/ep/zofis, from the Upper Cre- 

 taceous of Westphalia, may belong to this family. In Europe the 

 earliest undoubted member of the family is known by an imperfect 

 skull from the London Clay, which has received the name of Buck- 

 landium ; the affinities of this form are imperfectly known, but the 

 skull seems to approximate to that of Auchenoglanis of the African 

 rivers. In the Middle Eocene of Bracklesham, and the Upper 



