2 



BRITISH FOSSILS. 



on the surface. The other opercular bones are high and narrow ; 

 they are covered superficially with flattened imbricated scales of 

 ganoine. The coracoid bone is broad and flattened out posteriorly. 

 The superficial ornament is uniform with that on the opercular 

 bones. The rays composing the pectoral fins are long, and the 

 transverse articulations near their extremities are very numerous ; 

 they are about 1 2 in number No fulcral rays appear to have been 

 present in these fins. The ventral fins are situated rather behind 

 the centre of the body. They are of moderate size, and have several 

 strong elongated scales on their anterior margins. The impression 

 alone of the anal fin is preserved. This shows it to have been of 

 considerable size, and to have extended very far back, almost to 

 the commencement of the caudal fin. The latter fin is also, for the 

 most part, deficient in the specimen, although enough is seen to 

 prove its resemblance to this organ in Lejndohts. The most re- 

 markable feature in this fish is the dorsal fin. It originates about 

 half an inch behind the occiput, and extends from thence without 

 interruption to the commencement of the lobe of the tail. The 

 outline of the back is also very peculiar in this fish. It rises 

 rather abruptly from the head to the dorsal fin, it then declines 

 gradually for about 2 inches, and thence slopes suddenly to the tail. 

 In lieu therefore of the graceful sweeping form which generally 

 prevails in this family, we have a somewhat angular outline of 

 back, which, together with the prominent snout, has suggested the 

 specific name. The dorsal fin is fortified by a set of fulcral scales 

 and spines on its anterior margin, but these are by no means so 

 strongly developed as in the species of Lepidotus most nearly allied 

 to this genus. The fin rays are thick, they bifurcate at a short 

 distance from their base, and are thence traversed by numerous 

 approximpvte transverse divisions. Before the point of bifurcation 

 these articulations are few. It is impossible to count the number 

 of the rays, as the fi*n is by no means perfect, they cannot, however 

 be computed at fewer than 40. The scales are very uniform in size 

 and shape in all parts of the body, except in the vicinity of the 

 tail. The exposed surface is rhomboidal, the vertical axis being the 

 longest. The angles vary but slightly from right angles. The upper 

 posterior ones being slightly acute, the lines of union between the 

 scales in the dorso-ventral series are oblique to the longitudinal axis 

 of the body ; the more so from the direction of the series themselves 

 being at a considerable angle downwards and backwards. There 

 are from twelve to fourteen scales in each series. The lateral line 

 is nearly straight ; it occupies the sixth row of scales in descending 



