374 



A HISTORY OF FISHES 



gill-clefts, and with two dorsals and one anal fin, the former not 

 preceded by spines (Figs, i; 23G; 32A; 34b), includes the Sand 

 Shark {Odontaspis), and Elfin Shark (Scapanorhynchus) , constitut- 

 ing the family Odontaspidae; the Mackerel Sharks {Lamna), 



//arcobatidae 



Raiidae 

 Pri,tCdac I Tr^S^ncdae 



/ihinobatidae j y ^^ ^ 



/^obididae 



Scylior/iinidae 

 C areolar iTtidcLC 



7^U tiophoridae 



HYPOTREMATA 



Fro t.ospi n.c, •.: ida 

 Squatinidae 



JS<fucUicL 

 Coc.hUodoirLb'.dae '*^ p 



Mexanchidae 

 Chiami^dos el a ch ida t 



D 



/C/-/7r!y'0T0MI 



ACANTHQDIJ 



^LrUROPlTRYQil 



Fig. 134. PHYLOGENETIC " TREE " OF THE CLASS SELACHII. 



Sub-classes, orders and families are shown. 



Porbeagles (Isurus)^ Man-eater Sharks {Carcharodon) , Basking 

 Shark {Cetorhinus) , and Thresher Shark {Alopias), of the family 

 Lamnidae; the large and varied family Orectolobidae, including 

 the Carpet Sharks {Orectolobus) ^ Tiger Sharks [Stegostoma), Nurse 

 Sharks {Gi?iglymostoma) and Whale Shark {llhineodon) ; the Dog- 



