AnalytiGol Synopsis of the Order of Squali. 403 



Synopsis. 

 Nostrils in front near the middle, and with grooves extend- 

 ing toivards the eyes. Head hammer-shaped, much 

 produced laterally. , Eusphyra. 



Nostrils near the eyes. 



Nostrils simple, with the frontal grooves rudimentary or 



obsolete. Head reniform. Reniceps. 



Nostrils with grooves extending in front towards the middle. 



Head hammer-shaped. Cestracion. 



Genus Reniceps Gill. 

 Type Reniceps tiburo Gill. 



Genus Cestracion Klein. 

 Sphyrna Baf, 1810. 

 Sphyrnias Haf.^ 1815. 

 Cestrorhinus Blainville, 1816. 

 Zygeena Cuvier^ 1817. 

 Platysqualus Swainson, 1839 (P. tiburo Sw.=Zjg2iQ,n2i tudes 



Val.) 

 Sphyra Yanderhoeven. 



Type Cestracion zygsena Gill. 



Genus Eusphyra Gill. 

 Type Eusphyra Blochii Gill. 



Family ALOPECOIDvE, Otoen. 

 Genus Alopias Raf.^ 1810. 

 Alopecias Milller and Ilenle^ 1838. 

 Type A\o\>\.?i% vulpes Bon. 



Family HETERODONTOID^ Gill. 

 Genus Heteropontus Blainville^ 1816. 

 Cestracion Ciivier, 1817. 



Type Heterodontes Philippii Blainville. 



