486 



MESOZOIO TIME — REPTILIAN AGE. 



is a broad fish, six to twelve inches long ; another, B. superbus, sometimes thir- 

 teen inches long. About twenty-five genera of Cycloids and fifteen of Ctenoids 



Fig. 791. 



Teliost.— Osmeroi 



iensis(XJ4). 



have thus far been recognized in the Cretaceous. Ganoids were numerous in 

 species, of the genera Belonostomua, Caturus, Lepidotus, etc., besides others of 

 the Pycnodont family, Pycnodus, Gyrodus, etc. Sharks of the Hybodont 

 family were sparingly represented; Cestraciont remains were very common, es- 

 pecially of the genera Ptychodus and Acrodus. Teeth of Squalodonts are occa- 

 sionally met with, of the genera CarcJiarias, Lamna, Oxyrhina, Odonta^pis, etc. 

 b. Beptiles. — Fig. 792, Mosusaurus Hofmanni, head, from the Chalk at Maes- 

 trieht, one-eighteenth the natural size. Other remains of this species have been 



.Fig. 792. 



Mosasaurus Hofmanni (X j^ )• 



found at Lewes in England. In general character it is related to the Lizards ; 

 but the short and stout humerus has led to the suggestion that it may have been 

 a swimming species, and therefore a wholly new type. 



