208 MR. A. S. WOODWARD ON BUCKLANDIUM DILUVII. [Apr. 2, 



4. Note on Bucklandium diluvii, Kouig, a Siluroicl Fish from 

 the Loudon Clay of Sheppey. By A. S.Mixn Woodward, 

 F.Z.S., F.G.S., of the British Museum (Nat. Hist.). 



[Received March 30, 1889.] 



(Plate XXII.) 



In his well-known ' Icones Fossilium Sectiles,' pi. Tin. no. 91, 

 Koiiig figured a remarkable fossil from the London Clay of the Isle 

 of Siieppey, whidi he mentioned in the text as not certainly deter- 

 minable, but generally regarded by the anatomists who had examined 

 it as pertaining to some type of Lizard. In 1843 Morris ' recognized 

 the piscine nature of this fossil and assigned it to the Acantho- 

 pterygian Ephippus ; while Pictet " afterwards suspected that it might 

 be identical with the so-called Gli/ptocepkalus of Agass\z, which had 

 not been described, but was considered to pertain to an early Eocene 

 type of Scleroderm Teleosteau. 



The unique specimen in question is preserved in the British 

 Museum, where it has long been piaced among the fossil fishes of 

 uncertain position by Mr. William Davies ; and in the Reports of 

 the last meeting of the British Association (p. 079) the present writer 

 has pointed out that it represents the head and pectoral arch of the 

 earliest undoubted Sduroid fish hitherto discovered. The original 

 figures of Konig, however, do not suffice for the demonstration of its 

 characters ; and it is tlie object of the present note briefly to describe 

 the main points with the aid of the accompanying Plate XXII. 



The fossil exhibits the hinder half of the roof of the skull, with 

 the greater portion of the pectoral arch in position, though slightly 

 bent backwards ; and the mass of anchylosed vertebraB, with the 

 base of the cranium, is displaced downwards and tlirown beneath the 

 clavicles. All the bones are remarkably strong, and the exposed 

 surfaces are ornamented with irregularly scattered pointed tubercles; 

 but in the extrication from the hardened clayey matrix the precise 

 form of the inner elements has unfortunately been destroyed. 



The head must have been originally at least as deep as broad (Plate 

 XXII. fig. 1), and the roof exhibits very little flattening, but is strongly 

 arched from side to side (fig. 2). Posteriorly, the supraoccipital 

 {so.) projects in the usual manner, probably to meet a dermal plate 

 upon the nape; and the posttemporal element (pt.) seeir.s to be 

 merged with the bones of the postero-lateral angles of the cranium. 

 The supraoccipital has been partly broken during extrication from the 

 matrix, but a sharp median ridge is seen to extend throughout its 

 length, and from this on each side there is a steep slope. The 

 frontals {fr.) probably meet in front, and the central crest then 

 disappears. All the crauial bones, hov\ever, are indistinguishably 



' J. Morris, ' Catalogue of British Fos^sils," p. 193. 



- F. J. Pictet, ' TraiLc do Palcoutylogie,' 2ud edit., vol. ii. p. 123. 



