276 HISTORICAL PALZONTOLOGY. 
the great modern order of the Bony Fishes or Zéleosteans 
makes its first appearance in the Upper Cretaceous rocks, 
where it is represented by forms belonging to no less than 
three existing groups — namely, the Salmon family (Sad- 
monide), the Herring family (C/upecd@), and the Perch family 
(Percidz). All these fishes have thin, horny, overlapping 
AT 
Hh 
Fig. 208.—1, Beryx Lewesiensis, a Percoid fish from the Chalk ; 2, Ossxeroides 
Manteliz, a Salmonoid fish from the Chalk. 
scales, symmetrical (“ homocercal”) tails, and bony skeletons. 
The genus Beryx (fig. 208, 1) is one represented by existing 
species at the present day, and belongs to the Perch family. 
The genus Osmeroides, again (fig. 208, 2), 1s supposed to be 
related to the living Smelts (Osmerus), and, therefore, to 
belong to the Salmon tribe. 
No remains of Amphibians have hitherto been detected in 
any part of the Cretaceous series; but eff/es are extremely 
numerous, and belong to very varied types. As regards the 
great extinct groups of Reptiles which characterise the Meso- 
zoic period as a whole, the huge “ Enaliosaurs” or “‘ Sea- 
Lizards” are still represented by the /cAthyosaur and the 
Plesiosaur. Nearly allied to the latter of these is the £/as- 
mosaurus of the American Cretaceous, which combined the 
