FOSSIL FISH. 405 



thought proper to refer it to the above named species, which 

 exists in the seas of Japan. 



Tetraodon hispidus. An impression of the same nature as 

 the preceding, but still smaller, more orbicular, with the head 

 less pointed, and the forehead more plane. The figure and 

 position of the pectoral fins, and the number of rays of the 

 tail (ten), induced M. Volta to regard this ichthyolite as the 

 Tetraodon hispidus of the Mediterranean ; but it is a query if 

 it differ much from the preceding. 



DiODON. Diodon reticulatus? Volta, in the work which 

 we have mentioned, gives the description and characters of a 

 true Diodon reticulatus^ under this head ; but it is very doubt- 

 ful, to say no more, that the fossil which he refers to it, and of 

 which but a single specimen has been found, appertains in 

 reality to this species. 



Pal^obalistum. It appears indubitable, according to M. 

 de Blainville, that an impression figured in the same work, 

 very imperfectly terminated, by no means represents the dio- 

 don orbiculatus, as M. Volta will have it ; nor, in fact, a diodon 

 at all. The form of the tail, and especially some thick teeth 

 which remain near the mouth, though a little in disorder, 

 clearly prove the contrary. It is much more like a species of 

 Balistes, as was the opinion of M. Faujas. M. de Blainville 

 thinks it should form a small distinct genus, in consequence of 

 the form of the teeth ; he names it, provisionally, Palccohalis- 

 turn, and the species P. orhiculatum. 



Centriscus. C. longirostrisf De Blain. This is certainly 

 a species of this genus, very much approximating to the veli^ 

 taris of Pallas, but differing in the greater proportional length 

 of the muzzle, which equals one half of the body, and is also 

 much more slender. The first sting of the first dorsal fin, is 

 also considerably longer. 



C. aculeatus, De Blain. M. Volta, not having found ia 

 authors, and especially in Bloch, who was evidently his guide,, 

 any figure which resembled this ichthyolite, has thought proper, 



