ORDER TELEOSTEI. 



999 



the supraoccipital region, by the unequal size of the cylindrical or 

 compressed teeth, and the presence of at least one large spine in 

 the pectoral and pelvic fins. Ichthyodectes apparently differs mainly 

 by its equal-sized teeth. Another genus is Daptinus, of the North 

 American and English Cretaceous ; the English species apparently 

 connecting the typical American one with Ichthyodectes. Saurodon 

 is known from the Upper Greensand of New Jersey ; while we may 



937. — The anterior portion of the skeleton of Portkeus molossus ; from the Cretaceous 

 of North America. Greatly reduced. (After Cope.) 



provisionally place in this family the imperfectly known Tomognathus, 

 of the English Chalk, in which the teeth were anchylosed to the 

 jaws, without sockets, and had subcylindrical crowns enamelled 

 superiorly. 



As a probable Saurodont, of which the family position cannot be 

 determined, may be mentioned Gigantichthys (Titam'chthys), founded 

 upon teeth of very large size, from the Cretaceous of Egypt. 



Family GonorhynchiDtE. — We may now briefly mention five 

 small existing families related to the Salmonoids and Clupeoids. 

 The first of these is now represented only by a single species of 

 Gonorhynchus found on the coasts of South Africa, Australia, and 

 Japan. Closely allied, however, is Notogoneus, from the Eocene of 

 Wyoming, which is mainly distinguished by its dentition. 



Family Osteoglossid.e. — The second family is now represented 

 by Osteoglossum of South Africa, Sumatra, and Queensland ; the 

 huge Arapaima of the Brazilian rivers ; and Heterotis of several of 

 those of South Africa ; thus presenting a striking example of discon- 

 tinuous distribution. The only known fossil is Dapedoglossus, of 

 the Eocene of Wyoming ; a feature in distribution analogous to the 

 occurrence of the genus Notogoneus of the preceding family in the 

 same locality. 



Family Chirocentrid.e. — The genus Chirocentrus, of the Indian 

 Ocean, the sole existing member of this family, probably occurs in 

 the Eocene of Sumatra. Chiromystus, from the Eocene of Brazil, 

 may perhaps be referable to this family, although it is not certain 



VOL. II. H 



