10. REPTILES OF THE TRIAS. 549 



&c, and some peculiar Ammonites.* The Radiaria consist 

 of a few Star-fishes, Cidares, Pentacrinites, and Encrinites. 

 Of the latter, a most beautiful form of this family of 

 Crinoideans is exclusively found in the Muschelkalk. 



This is the Lily E tier inite {Ligyi. 124), so named from 

 the supposed resemblance of the animal, when in re- 

 pose, to a closed lily : in the lecture on Zoophytes I shall 

 describe this elegant fossil more particularly: the speci- 

 mens hitherto obtained are from the neighbourhood of 

 Hanover. 



9. Fishes of the Trias. — The bone bed that inter- 

 venes between the Lias and Trias (ante, p. 529), contains 

 teeth and dorsal rays of numerous small fishes of the genera 

 Acrodus, Ceratodus, Gyrolepis, Hybodus, and Nema- 

 canthus; similar remains occur, but very rarely, in the 

 sandstones and conglomerates. One of the most striking 

 ichthyological features of the Triassic and Permian deposits, 

 is the prevalence of fishes of the genus Palceoniscas, of 

 which several species abound in the marls, sandstones, and 

 limestones, of England, Europe, and North America. These 

 fishes belong to the ganoids with heterocercal tails, and 

 are covered with rhomboidal scales, which in some species 

 are very small, and in others large. In certain localities 

 the small species are sometimes found in groups of more 

 than two hundred individuals on a slab of stone not 

 exceeding two feet square. As only one species of the 

 genus has been identified in the Trias, the Pakeonisci are 

 more properly characteristic of the Lower New Eed, or 

 Permian system. 



10. Reptiles of the Trias. — The Triassic strata not 

 only contain teeth and bones of several remarkable reptiles, 

 but also bear the foot-marks, or imprints of the feet, of 

 many animals, both bipeds and quadrupeds, of whose 

 existence no other traces have, as yet, been discovered. 



* Termed Ceratites. See Mr. Lyell's " Elements," vol. ii. p. 92. 

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