W. Davies — Type Fossil Fishes in the British 3Iuseum. 209 



the window recesses, and in a portion of wall case 7. As this Order 

 comprises those fishes having a more or less cartilaginous skeleton, 

 the parts preserved are chiefly detached portions, as teeth, bony 

 palates, defensive and dermal spines, and vertebrae. But specimens 

 of the Eay family have been found preserved entire in the litho- 

 graphic stone deposits and in a fissile Limestone, of the Cretaceous 

 Period, in the Lebanon. 



The other Orders (the Ganoid, Ctenoid, and Cycloid) are arranged 

 in and upon the wall cases 1 to 6 inclusive, in a large, instructive, 

 and continuous series, where every diversity of form and detail of 

 anatomical structure, as yet known, of each Order or group, may be 

 compared and studied — from specimens derived from the most ancient 

 deposits in which fishes are found, up to the most recent ; exhibiting 

 every variety of rock-matrix in which their remains have been pre- 

 served. 



In a portion of wall case 7 are placed for exhibition those Fishes 

 whose exact place in the system of arrangement is not determined ; 

 and of genera and species which have not been described. 



The collection, although very far from perfect in regard to the 

 number of known and described genera and species, is fairly repre- 

 sented as regards families. It contains examples of nearly 300 

 genera and about 700 species, many of which are extremely rare, and 

 some probably unique. Much of its value is due to the gems of 

 many private collections, which have been acquired from time to 

 time. Firstly, may be mentioned that of the late Dr. Mantell, whose 

 zeal as a collector, and whose skill in developing his fine series of 

 Chalk and Wealden Fishes, were well known. It was from his museum 

 that Agassiz obtained most of the specimens for his descriptions and 

 figures of the fishes of these deposits. Subsequently, the late Mr. 

 F. Dixon's collection was obtained ; so rich in these remains from 

 the Tertiary and Chalk formations of Sussex, many of which are 

 figured in his work on the Geology and fossils of that county.^ More 

 recently examples from the London Clay of Sheppey and the Chalk 

 of Kent have been added from the collections of Dr. Bowerbank and 

 of Mr. Toulmin Smith, and a remarkably fine collection made by 

 Dr. Haberlein from the Lithographic stone-quarries of Bavaria. 



In the subjoined catalogue references will be found to a few speci- 

 mens which, although not absolutely the types, yet, from the works 

 of acknowledged authority and reference in which they have been 

 figured and described, may be considered as typical examples. These 

 references are marked with an asterisk. 



ACRODUS, Ag. 



— AnningicE, Ag. {spines), Geol. Mag. Vol. I. p. 37, PI. 4. L. Lias, Lyme 



Regis. 



— Illingworthi, Eg. {teeth), Dixon, F. S. p. 361, pi. 30, fig. 11. Chalk, Sussex. 



— ,, Eg. Dixon, F. S. p. 361, pi. 30, f. 12. 



ACROGNATHUS, Ag. 



— Boops, Ag. P. F. torn. 5, p. 108, tab. ^oa, figs. 1-4. Clialk, Lewes. 



ACROTEMNUS, Ag. 



— Faba, Ag. P. F. torn. 2, pt. 2, p. 203, tab. 66a, figs. 16-18. ib. loc. 



1 The fishes are described by Sir Philip de Malpas Grey Egerton, Bart,, F.fi.S. 



VOL. Vni. NO. LXXXIII, 14 



