FOSSIL FISH. 421 



nearly of a lozenge form ; the anterior half of the dorsal fin, 

 which is almost square, is remarkable for its great height ; the 

 dorsal fin is preceded by four small spines, and terminated in 

 contact with the caudal fin ; the anal, though equally pro- 

 longed, is much less raised, though a little more behind than 

 in front. Four or five vertical bands are to be seen on this 

 ichthyolite, of a deeper colour than the rest. 



C. velifery De Blain. Kurfus velifer, Volta. This is one 

 of the most common and best preserved ichthyolites of Vestena 

 Nuova ; all the characters of Chaetodon are easily recognized 

 in it. But this species differs from all that are known, in the 

 magnitude of the first half of the dorsal fin, which is triangular, 

 and which commences immediately above the nape, and espe- 

 cially in the magnitude of the ventral fins ; the anal fin, though 

 tolerably long, is very low, and yet proceeds decreasingly from 

 the first ray to the last : the pedicle of the tail is very narrow. 



Zeus. The Zeus triurus, and the Z. vomer of Volta are 

 indubitably one and the same species, and M. de Blain ville 

 thinks that they should form a distinct species of Chcetodon 

 rather than of Zeus, The most remarkable characters consist 

 in the convexity of the ventral line^ much more considerable 

 than that of the back ; in the dorsal fin, which has but a small 

 part more elevated in front ; and finally, in the anal, which is 

 very long and very low through its entire extent. 



Zeus plafessa, De Blain. In this genus must be placed 

 the rather incomplete fossil figured by M. Volta under the 

 name of Coryphcena apoda^ to which it is quite evident that it 

 cannot belong. Its general contour is that of a chaetodon, or 

 of a Zeus : the dorsal fin commences a little behind the nape ; 

 the first part is more elevated, and has six or seven tolerably 

 long and simple rays, and the fin is afterwards continued very 

 low, as far as the pedicle of the tail, which is very narrow ; the 

 anal fin has nearly the same form as the second part of the 

 dorsal, and there are neither pectoral nor ventral fins ; this, 

 however, must be attributed to the changes which the ichthy- 



