ANIMALS. 227 



and distinct. The scales themselves are large, and of very uniform size over the 

 whole body. The specimens hitherto found are not in a condition to show the 

 superficial characters of the scales, the impressions of the under-sides alone being 

 preserved. The dorsal fin is placed much nearer the tail than in any other species : 

 in this respect, but in no other, Palaoniscus catopterus resembles the genus Catopterus 

 of Mr, Redfield. The tail is decidedly heterocerque. It is altogether so distinct from 

 the other FalcBonisci, that it is recognisable at first sight." A slab presented to 

 the Geological Society by Mr. Green, exhibits, on a surface not exceeding two feet 

 square, above 250 specimens. 



Palaoniscus catopterus occurs in a quarry of red sandstone at Rhone Hill, in the 

 parish of Killyman about three miles east of Dungannon, Ireland. 



Family PYCNODONTiDiE, Agassiz. 



Genus Platysomus, Agassiz. 



Rhombus, Wolfart. 

 Stromateus, Blainville. 

 Uropteryx, Agansh. 

 Globulodus, Munster. 



For the latest pubhshed account of this singular genus, and the reasons for 

 removing it from the heterocercal Lepidoids to the present family, the reader is 

 referred to a very admirable paper by Sir Philip de Malpas Grey Egerton, Bart., M.P., 

 inserted in the ' Q,uarterly Journal of the London Geological Society,' vol. v, part i, 

 pp. 329-332. 



Platysomus macrurus, Agassiz. Plate XXVI, fig. 1 a. 



Fossil fish ; genus not determined, Sedgwick. Trans. Geol. Soc. Lond., 2d series, 



vol. iii, p. 118, pi. xii, figs. 1, 2, 1829. 

 Uropteryx undulatus, Agassiz. Msc. Walchner, Geol., p. 270. 

 Platysomus macrurus, „ Poiss. Foss., vol. ii, p. 1/0, pi. xviii, figs. 1, 2. 



— — ,, Morris, Catalogue, p. 202, 1843. 



— — » Rep. 13th Meet. Brit. Assoc, p. 198, 1844. 



— — „ De Verneuil, Bull. Soc. Geol. de France, 2™" serie, 



vol. i, p. 39, 1844. 

 — „ Geol. Russ., vol. i, p. 227, 1845. 



— — „ Tennant, Strat. List, p. 89, 1847. 



— — „ King, Catalogue, p. 15, 1848. 



— — » Howse, Trans. T. N. F. C„ vol. i, p. 234, 1848. 



— — ,. Egerton, Quart. Journal Geol. Soc, vol. v, part i, 



p. 329, fig. i, 1849. 



This appears to be one of the rarest of the Fishes of the Permian System. When 

 Agassiz was engaged upon his great work on ' Fossil Ichthyology,' he had not an oppor- 

 tunity of examining the then unique specimen from East Thickley, figured in the ' Transac- 



