MR J. W. GREGORY ON" THE MALTESE FOSSIL ECHLNOIDEA. 619 



Genus Prenaster, Desor, 1853. 



Species l. Prenaster excentricus, "Wright, 1855. 

 Synonymy — 



Perieosmus excentricus, T. "Wright, 1855, "Foss. Echinod. Malta," Ann. Mag. Nat. Hist. (2), xv. pp. 



195,196. 

 Prenaster „ T. Wright, 1864, "Foss. Echinidse Malta," Quart. Journ. Oeol. Soc, xx. 



p. 487, pi. xxii. f. 3. 



Types. — ? 



Distribution. — Malta — Upper Coralline Limestone (Brit. Museum). 



Genus Brissus, Leske, 1778. 



Species 1. BrisSUS latus, Wright. 

 Synonymy — 



Brissus latus, T. Wright, 1855, "Foss. Echinod. Malta," Ann. Mag. Nat. Hist. (2), xv. pp. 

 181, 183, pi. v. f. 1. 

 „ „ E. Desor, 1858, Syn. ^ch. foss., pp. 404, 405. 



T. Wright, 1864, "Foss. Echinidaj Malta," Quart. Journ. Geol. Soc, xx. p. 485. 



>> >) 



Type. — Coll. Earl of Ducie. 



Distribution. — Malta — Upper Coralline Limestone (Coll. Brit. Mus., Geol. Soc). 



Species 2. Brissus imbricatus, Wright, 1855. 

 Synonymy — 



Brissus imbricatus, T. Wright, 1855, "Foss. Echinod. Malta," Ann. Mag. Nat. Hist. (2), xv. pp. 



183, 184. 

 „ „ T. Wright, 1864, "Foss. Echinidse Malta," Quart. Journ. Geol. Soc, xx. p. 



486, pi. xxii. f. 2. 

 ,, „ G. Seguenza, 1869, "Posiz. stratig. Olyp. alius," Atti Soc. Ital. Sci. Nat., xii. 



p. 658. 

 „ scillm, (pars) E. Desor, 1858, Syn. itch, foss., pp. 403, 404. 



Type.— Brit. Mus., E. 1867. 



Distribution. — Malta — Upper Coralline Limestone. Italy — Pianosa (Tortonian ?). 



Remarks. — Dr Wright gave no figure of this species with his original diagnosis, and 

 M. Desor was led by this to suggest that it was a synonym of Brissus scillm, Ag., which 

 is itself a synonym of B. unicolor, Leske. # Dr Wright's figure, however, in 1864, 

 shows that the two species are very distinct. 



* Gat. rais. Ann. Sci. Nat. Zool, 1847 (3), viii. p. 13. 



