SÜB-CLASS VI 



TELEOSTEI 



95 



Fisodus, Owen. Large hemispherical or flattened crushing teeth on the 

 parasphenoid. Closely resembling existing Alhula. Lower and Middle Eocene 

 of England and Belgium. 



Family 4. Ichthyodectidae. Crook.i 



Large extind predaceous fishes, with a row of strong conical teeth fixed in sockets 

 on the margin of the jaws. Upper jaw formed hy short and deep preniaxilla, and 

 long stout maxilla ; mandihle deep, truncated in front, without any presymphysial 

 hone. Vomer and parasphenoid toothless ; palato-pterygoid arch with patches of 

 small teeth. Paired fins composed of a very hroad, anterior, and numerous narrower 

 rays, finely divided and articulated quite at the distal end. Dorsal fin short and 

 remote ; anal fin not much extended ; caudal fin forked, Cretaceous. 



This family is very closely related to the existing Chirocentridae, of which 

 only one genus (Chiro- 

 centrus) is known, in- 

 habiting the Indian 

 Ocean. 



Fortheus, Cope 

 (Xiphactinus, Leidy ; 

 Hi/psodon, Ag. p.p.), 

 (Fig. 171). Po werf ul 

 iishes, sometimes of 

 gigantic size. Teeth 

 of variable size, oval 

 in transverse section. 

 Palatine movably 

 articulated with eth- 

 moid, with hammer- 

 shaped thickening. 

 Eye with ossified 

 sclerotic ; three sub- 

 orbital plates. Oper- 

 culum well developed 

 and large. F. molossus, 

 Cope (Fig. 171), and 

 other species occur in 

 the Chalk of Kansas, U.S.A. F. mantelli, Newton, and other species in the 

 Chalk and Gault of England, France, Belgium, Bohemia, and Saxony. 

 Fragments also in Cretaceous of Rolling Downs, Queensland. 



Ichthyodedes, Cope. As Fortheus, but smaller, and teeth of uniform size. 

 Chalk of Kansas and England. 



Gillicus, Hay. Like the preceding, but teeth small and fringe-like. 

 Upper Cretaceous ; Kansas. 



Spathodactylus, Pictet. Type specimen displaying fins. Neocomian : 

 Voirons, Switzerland. 



^ Crook, A. R., Ueber einige Knoclienfische aus der mittleren Ki-eide von Kansas (Palaeoutogr. 

 vol. XXXIX.), 1892. — Loomis, F. B., Die Anatomie und die Verwandtschaft der Ganoid und 

 Knochenfische aus der Kreide von Kansas (Palaeoutogr. vol. XLVL), 1900. 

 of the Upper Cretaceous (Univ. Geol. Surv. Kansas, vol. .VI.), 1900. 



Head of Porthms molosms, Cope. Niobrara Cretaceous ; Fox Cafton, 

 Kansas. V4 '^at. size (after Cope). 



-Steivart, A., Teleosts 



