Xll 
INTRODUCTION. 
France. In Permian rocks, the skeletons of Pleuracanthus and its 
allies are well preserved (p. 3), and the dentition of Janassa is 
satisfactorily known (p. 35). Triassic Elasmobranchs are only 
recognizable at present by detached teeth and spines, which have 
been described from the German and French Muschelkalk by H. von 
Meyer \ E. E. Schmid 2 , P. Gervais 3 , and others. 
The genera of Liassic age are most completely known from the 
fossils of Lyme Pegis, Dorsetshire, some being described by Charles- 
worth 4 , Egerton 5 , Day 6 , and J. W. Davis 7 , and much further 
information added by specimens noticed in the following Catalogue. 
A remarkably complete example of a Cestraciont dentition has also 
been discovered in the Lias of Wurtemberg 8 . 
The Lower Oolites have yielded no Elasmobranch fossils of 
importance, but fragmentary teeth and spines are noticed by 
Phillips 9 . The remains from the Middle Oolites are also unsatis¬ 
factory ; but the occurrence of Lithographic Stone in the Upper 
Oolites of the Continent is a fortunate circumstance, on account of 
its excellent adaptation for the preservation of delicate structures 
and impressions. Many Selachii have been described from this 
deposit in Germany by H. von Meyer 10 , A. Wagner 1 11 , 0. Fraas 12 , 
and others; and those from its French equivalent are made known 
by Thiolliere l3 . 
Teeth and spines of Cretaceous Selachii are described from 
England by F. Dixon 14 , and by various later writers in scattered 
1 H. von Meyer, “ Fische etc. aus dem Muschelkalk Oberscklesiens,” Palee- 
ontographica, vol. i. (1849), pp. 220-234, pis. xxviii., xxx. 
2 E. E. Schmid, “ Die Fischzahne der Trias bei Jena,” Nova Acta Acad. Cses. 
Leop.-Car. vol. xxix. no. 9 (1861). 
3 P. Gervais, Zoologie et Paleontologie Frai^aises, 1852, Explic. PI. pp. 
12, 13, pi. lxxvii. 
4 Hybodus delabechei (p. 259). 
6 Palceospinax (p. 321). 
6 Hybodus delabechei (p. 259) and Acrodus anningice (p. 289). 
7 Palceospinax (p. 322). 
8 Bdellodus (p. 321). 
9 Prof. J. Phillips, Geology of Oxford and the Valley of the Thames, 1871. 
10 Squatina speciosa (p. 67) and Asteroderrnus platypterus (p. 84). 
11 Cestracion falcifer (p. 332). 
12 Squatina alifera (p. 65). 
13 Bhinobaius bvgesiacns (p. 78) and Belemnobcitis sisrnondce (p. 84). 
14 F. Dixon, The Geology and Fossils of the Tertiary and Cretaceous Forma¬ 
tions of Sussex, 1850. 
