486 



MESOZOIC TIME — REPTILIAN AGE. 



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

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



Fie. 791. 



Teliost.— Osmeroides Lewesiensis (X X A)- 



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

 species, of the genera Belonostomus, Caturm, Lepidotw, 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 Garcharias, Lamna, Oxyrhina, Odontaspis, etc. 

 b. Reptiles. — Fig. 792, Mosasaurus Hofmaimi, head, from the Chalk at Maes- 

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



Fig. 792. 



Mosasaurus Hofmaimi (X A )• 



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. 



