BRITISH POSSILS. 



Decade YIII. Plate IV 



PH0LID0PH0RU3 GEANULATUS. 



[Genus PHOLTDOPHORUS. Aoassiz. (Sub-kingdom Vertebrata. Class Piscas. 

 Order Goniolepidoti. Family Lepidostei. Sub -family Lepidostei homocerci. 2d Group. 

 Body elongated, more or less fusiform.) Dorsal fin small, opposite the ventrals; caudal 

 fin forked ; the lobes equil ; the base of the upper lobs invested with scales : teeth 

 villiform.]* 



Pholidophorus granulatas, Sp. Nov. 



Descri]}tion. — The genus Pholidophorus makes its first appear- 

 ance during the deposition of the lias, and contributes some of the 

 most characteristic forms of the fauna of that period. No less 

 than fifteen species are named and described from that formation 

 alone. The succeeding members of the oolitic period in Great Britain 

 are singularly deficient in species of this genus as compared with 

 the continental deposits of corresponding age ; for of the nineteen 

 oolitic species enumerated by Professor Agassiz in the " Poissons 

 Fossiles/' only one, Pholidophorus Flesheri, occurs in England. The 

 moi-e recent deposits have only furnished one species, the Pholido- 

 phorus ornatus of the Purbeck strata of Swanage. The single 

 specimen examined by Agassiz, and consequently the type of the 

 species, is a mere fragment, formerly belonging to the late Doctor 

 Mantell, but now in the collection of the British Museum. On 

 comparing this, the original, with the representation given in the 

 " Poissons Fossiles," an error becomes manifest in the position of 

 the dorsal fin. The impressions of some broken scales in the neigh- 

 bourhood of the tail have been mistaken for the rays of the dorsal, 

 and this character has been embodied in the text as distinctive of 

 the species, whereas the true rays of the dorsal fin are traceable in 

 the position which usually obtains in the Pholidophori, viz., the 

 middle of the back. The peculiar character of the scales is, however, 



[viii. iv ] 



* Poiss, Foss. vol. 2, p. 9. 



