BKITISH FOSSILS. 



Decade I. Plate VIII. 



GALERITES (DISCOI35EA) CYLINDRICUS. 



[Genus GALERITES. Lamarck. (Sub-kingdom Radiata. Class Echinodermata. 

 Order Echinidse. Family Cassidulidse.) Body more or less hemispherical, always tumid ; 

 ambulacra simple, continuous, radiant ; mouth central, inferior ; anus inferior, or sub- 

 marginal ; tubercles perforate.] 



[Sub-genus Discoidea. Body hemispheric, circular, fiat-based; tubercles in regular 

 series ; inside strengthened by strong ribs.] 



Synonyms. Galerites cylindricus, Lamarck (in 2nfl Ed., iii., p. 311). 

 Conulus Hawkinsii^ Mantell, Geol. Trans., New Ser., vol. iii,, part 1, 

 p. 208, Galerites Hawkinsii, Desmoui^ins, Tab. Syn., p. 254. Galerites 

 canaliculatus, Goldfuss, p. 128, pi. 41, f. 1. Scutella depressa and S. 

 hemisphcerica, Woodward, Geol. Norfolk, p. 52, t. 5, f. 4and 5. Discoidea 

 cylindrical Agassiz, Echin. foss. Suiss., part 1, p. 92, t. 6, f. 13. 15. 

 Desor, Monog. Galerites, p. 58, t. 8, f. 8-16. Agassiz and Desor, Cat. 

 Rais. des Echin., Ann. Sc. Nat., 3rd ser., vol. vii., p. 147. Galerites {Dis- 

 coidea) cylindrical Rcemer, Nord-Deutsch. Kreide Geb., p. 31. 



Diagnosis. G. {Discoidea) inflata^ magtia, hcemisphcerica seu {adultd)^ 

 suhcyliyidi ica I ventre plano^ ano parvo ; areis ambulacralibus tertiani 

 partem arearum inter ambulacralium cequantihus ; assulis ambulacralibus 5 

 ad assulam inter ambulacralem appositis. 



Desor, in his " Monograph of the Galerites," and Bronn, in his 

 " Index Palaeontologicus," refer to this beautiful fossil the figures 

 given by Leske of his Echinites quaterfasciatus and Echinites sexies- 

 fasciatus (Leske ap. Klein, t. 47, f. 3-5, and 50, f. 1 and 2, copied in 

 the " Enc. Meth." Echinus quadrifasciatus and Echinus sexfasciatus, 

 Gmelin, 3183 made two species of Galerites by Lamarck), considering 

 them as monstrous varieties ; but a careful inspection of the figures of 

 Leske, representing two casts, is sufficient to show that they are the 

 nuclei of species of the subgenus Galerites^ and not of the subgenus 

 Discoidea. Had they represented casts of monstrosities of G. cylindricus, 

 they would have exhibited the regularly arranged furrows caused by 

 the impressions of the internal ribs. The history of the species dates, 

 therefore, from its definition as such by Lamarck. Desmoulins and 

 Dujardins have confounded it with tertiary urchins, and added syno- 

 nyms to the Lamarckian name which do not belong to it. The best 

 [i. viii.] I 



