SUB-CLASS VI 



TELEOSTEI 



95 



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

 parasphenoid. Closely resembling existing Albida. Lower and Middle Eocene 

 of Enoland and Belgium. 



Family 4. Ichthyodectidae. Crook, i 



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

 on the margin of the jaws. Upper jaw formed by short and deep prernazilla, and 

 long stout maxilla ; mandible deep, truncated in front, withotit any presymphysial 

 bone. Vomer and parasphenoid toothless; palato-pterygoid arch with ])atches of 

 small teeth. Paired fins composed of a very broad, 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. 



Portheus, Cope 

 {Xiphactinus, Leidy ; 

 Rypsodon, Ag. p.p.), 

 (Fig. 171). Powerful 

 fishes, 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. P. molossus. 

 Cope (Fig. 171), and 

 other species occur in 

 the Chalk of Kansas, 

 Chalk and Gault of 



Fig. 171. 

 Head of Portheus molossiis, Cope. Niobrara Cretaceous ; Fox Cauon, 



Kansas. 1/4 nat. size (after Cope). 



species in the 

 and Saxony. 



U.S.A. P. mantelli, Newton, and other 

 England, France, Belgium, Bohemia, 

 Fragments also in Cretaceous of Rolling Downs, Queensland. 



Ichtliyodectes, Cope. As Portheus, 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. Ji., Ueber einige Knochenfische aus der mittleren Kreide vou Kansas (Palaeoutogr. 

 vol. XXXIX.), 1892. — Looviis, F. B., Die Anatoniie und die Verwaudtschaft der Ganoid und 

 Knochenfische aus der Kreide von Kansas (Palaeontogr. vol. XLVI.), 1900. — Stewart, A., Teleosts 

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



