358 THE WONDERS OF GEOLOGY. Lect. IV. 



Sphcerodus mammillaris. From Clayton chalk-pit. 



Dercetis elongatus. Lign. 74, page 349. Length 16 inches. South Down Fossils. 



Tab. xxxiv. figs. 10, 11. Tab. xl. fig. 2. Agass. Poiss. Foss. Vol. 



ii. tab. 66a, figs. 1 to 8. 



The above order comprehends three extinct genera, with three species. 

 Another species of Dercelis has been found in the chalk of West- 



Okder III. — The Ctenoidians, [ktzis, a cornb.) The scales of this 

 order are pectinated on their posterior margin, like the teeth of a 

 comb, and are composed of laminae of horn or bone, but have no 

 enamel. Lign. 68, fig. i, p. 339. 



Beryx Lewesiensis. (B. ornatus of Agassiz.) South Down Fossils. Tab. xxxiv. 



fig. 6. Tab. xxxv. Tab. xxxvi. Agass. Poiss. Foss. Vol. iv. 



tab. 14a. 

 radians. History of the County of Sussex. Vol. ii. Part ii. p. 15, fig. 22. 



Agass. Poiss. Foss. Vol. iv. tab. 14b, fig. 7. 

 microcephalics. Agass. Poiss. Foss. Vol. iv. tab. 4c, figs. 7 to 9. 



There are other species of Beryx in the chalk of Bohemia and West- 

 phalia ; and genera nearly related to Beryx, in the schist of Glaris. 



Order TV. — The Cyclo'idians, (kvkXos, a circle ) The scales smooth, 

 with a simple margin, composed of laminae of horn or bone without 

 enamel. Lign. 68, fig. 3, p. 339. 



Osmeroides Mantelli. (Salmo Lewesiensis of Mantell.) South Down Fossils. Tab. 

 xxx. fig. 12. Tab. xxxiv. fig. 3. Tab. xl. fig. 1. Agass. Poiss. 

 Foss. Vol. v. tab. 60o. 



To the above species belong the remarkable uncompressed specimens 

 now in the British Museum. 



Osmeroides Lewesiensis. Agass. Poiss. Foss. Vol. v. tab. 60c. (Salmo? Lewesi- 

 ensis of Mantell.) This species is more elongated than O. Mantelli, 

 and the number of rays in the dorsal fin is greater. 



granulatus. History of Lewes. Vol. i. plate xxix. fig. 13. The bones 



of the head, with the jaws and teeth, have alone been discovered. 

 Agass. Poiss. Foss. Vol. v. 



Enchodus halocyon. South Down Fossils. Tab. xxxiii. figs. 2, 3, 4. Tab. xliv. 

 figs. 1, 2. Agass. Poiss. Foss. Vol. v. tab. 25, figs. 11 to 6. 



Saurocephalus lanciformis. (Harlan.) South Down Fossils. Tab. xxxiii. figs. 

 7, 6. Trans. Geol. Soc. of Pennsylvania, Vol. i. p. 83. Agass. Poiss. 

 Foss. Vol. v. tab. 25, figs. 21 to 29. 



Saurodon Leanus. (Hays.) Trans. American Philos. Society, vol. for 1830, 

 plate 16. Agass. Poiss. Foss. Vol. v. tab. 25, figs. 17 to 20. 



Hvfrodon Lewesiensis. South Down Fossils. Tab. xxxiii. tig. 8. Tab. xlii. figs. 

 1 to 5. Agass. Poiss. Foss. Vol. v. lab. 25*. 



