382 Analytical Synopsis of the Order of Sqiiali. 



belonging to the same species, forms which are taken in the 

 '''•natural arrangement^'' as representatives of distinct genera in 

 different snb-families : Rafinesque and S wainson have alone the 

 merit of separating them ! 



14. — Prof. Richard Owen, in his " Lectnres on the Compara- 

 tive Anatomy and Physiology of the Vertebrate Animals, deli- 

 vered at the Royal College of Surgeons of England, in 1844 and 

 1846," accepted the order of Plagiostomi without its division 

 into suborders, and adopted the following families of sharks. 



Hybodontidse Example, Hybodus. 



Cestraciontidae Cestracion. 



Notidanidse Grey shark. 



Spinacidaj Piked dog fisb. 



Scylliidae Dog fish. 



Nictitantes Tope. 



Lamnidse Porbeagle. 



Alopeciidse Fox-shark. 



Scymniida3 . Greenland-shark. 



SquatinidfB Monk fish. 



Zygsenidse Hammer-head shark. 



The arrangement thus resembles the first classification of 

 Miiller and Ilenle, rather than the second, in the preservation of 

 the Nictitantes or sharks with the nictitating membrane as a true 

 family. The Odontaspides appear also to be considered as 

 Lamnidte. But the principal dift'erence is the position of the 

 Zygfenidai at the end of the sharks, where they had been before 

 almost placed by Cuvier in the second edition (1829) of his 

 Regno Animal, — for the latter had only placed after them the 

 Squatinse. This position of the Zyga^uidte does not appear to 

 be natural, as those fishes are evidently very nearly allied to the 

 other Nictitantes, difiering only in the lateral development of 

 the head, and the modifications necessarily induced thereby. 

 The highest rank to which they are entitled is that of a family 

 nearly allied to the Nictitantes with the normal squaloid form. 



