BRITISH 



FOSSILS. 



Decade VI. Plate III. 



LEPIDOTUS PECTINATUS. 



[Genus LEPIDOTUS. Agassiz. (Sub-kingdom Vertebrata. Class Pisces. Order 

 Goniolepidoti. Family Lepidostei. Sub-family Lepidostei horaocerci. 2d Group. Body 

 elongated, more or less fusiform.) Dorsal fin opposite the interval between the ventrals 

 and anal ; caudal fin large, with strong fulcral scales on the margins ; the base of the 

 upper lobe invested with scales ; teeth conical, obtuse ; scales rhomboidal, large and thick, 

 invested with a dense layer of ganoine.*] 



Synonym. — Lepidotus pectinatus^ Egerton, Proceedings of Geol. Soc, 

 1843, p. 184. 



Description. — The genus Lepidotus is one of the most interesting 

 in the Ganoid order of fishes, in a zoological point of view, as pre- 

 senting the best subjects for the examination of the structure and 

 development of the singular tegumentary investment upon which 

 Agassiz established the order, and in other respects as containing 

 numerous species, easily recognized, frequently in a good state of pre- 

 servation, and always characteristic of the age of the strata in which 

 they occur. Agassiz has described sixteen species in the " Poissons 

 Fossiles,'' and several new ones have been discovered since the publi- 

 cation of his work. I know few fossils more beautiful than the Lepi- 

 doti. The large size of some of the species, the rotundity of contour 

 (so frequently preserved by the rigidity of their dermal encasement 

 when every vestige of the endo-skeleton and its associated organs has 

 disappeared to be replaced by indurated mud), the ornamental sculp- 

 turing of the cranial bones, and above all, the regularity and 

 brilliancy of the scales, and the delicate tracery so frequently en- 

 graven on the glistening enamel, all combine to render the remains 

 of this genus most attractive, and little liable to be overlooked by 

 the most careless observer. The species range from the chalk to the 

 lias inclusive ; one only occurs in the cretaceous series, four in the 

 wealden, six or seven in the oolites, and eight in the lias. From the 

 latter formation at Whitby the subject of this article is derived. It 

 measured, as far as can be calculated from an imperfect specimen, 



[VI. iii.] 



* Agassiz, Poiss. Foss., vol. ii. p. 233. 



6 D 



