34 



PISCES 



CLASS I 



of rather doubtful relationships. Most species described under this name 

 referable to Lamna and Odonfaspis. Cretaceous and Eocene. 



Lamna, Cuv. Second dorsal fin and the anal very small. Side of tail with 

 keel. Teeth as in Odontaspis, but the principal cusp usually somewhat broader 

 and the lateral denticles 

 larger. Very abundant 

 in the Chalk, Tertiaries, 

 and existing seas. 



Oxyrhina, Ag. (Fig. 

 68). Only differing from 



Otochis appendieu- 

 latus, Ag. Planer ; 

 Quedlinburg. 



OtocUis ohUqmis, Ag. External 

 aspect of tooth. Eocene ; Sheppey. 



Fig. 6S. 



0.cijrlLinaplicatilis, Ag. Mio- 

 cene ; Neudorfl, Hungary. 



Lamna in the teeth lacking lateral denticles. Cretaceous to Recent. 0. 

 mantelli, Ag., the commonest Cretaceous species both in Europe and North 

 America, the nearly complete dentition known from Kansas. 0. desori, Ag., 

 chiefly Lower Tertiary ; 0. hasfalis, Ag., 

 chiefly Upper Tertiary. 



Alopecias, M. and H. Tertiary and 

 Recent. 



Corax, Ag. (Fig. 69). Known only 

 by low triangular teeth with sharp, 

 serrated edges, and a large root. Com- 

 mon ill the Middle and Upper Cre- 

 taceous. C. prisfodontus, Ag., from 

 Maastricht, North Africa (Fig. 69), and 



( 'iirux imstoiloiittts, Ag. 

 Upper Chalk ; <Jasis of 

 Dat-liel, Libyan Pesert. 



Carcharuclou megalodon, Ag. Miocene ; Malta. 



supposed Eocene of Alabama. C.falcafns, Ag., European and North American 

 Cretaceous. 



Carcharodon, M. and H. (Fig. 70). Second dorsal fin and the anal very 

 small. Side of tail with keel. Teeth very large and triangular, with 

 serrated lateral edges, flattened outer face, convex inner face. One Upper 



