BRITISH FOSSILS. 



Decade V. Plate III. 



ECHINOPSIS ROTATA. 



[Genus ECHINOPSIS. Agassiz. (Sub-kingdom Eadiata. Class Ecliinodermata. 

 Family Echinidae.) Body inflated, depressed, or sphseroidal ; primary tubercles in each 

 area small, perforated, and borne on plain, not crenulated, bosses ; pores in single file, or 

 in oblique ranks of threes ; mouth but slightly notched.] 



[Sub-genus Pedina, Agass. Pores in ranks of threes.] 



Diagnosis. jE". sesquiuncialis, rotunda vel suhpentagona, granulosa, 

 tuherculis primariis lO-radiatis muricata, ambulacralibus distincte binis, 

 parvis; inter ambulacrorum (in serie singula 13-14) superne majoribus 

 conspicuiSf infra arctius aggregatis minoribus : secundariis, no7inullis ad 

 orem exceptis majoribus, mi?iutis ; ore modico. 



Synonyms. Pedina rotata, Agassiz (1840), Ecliin. Suiss., pi. 15. fig. 4-6. 

 P. ornata, ih.i \_Diadema micrococcon, Desmoulins (1837), Tabl. 



Synon. des Echin., p. 314.] Pedina rotata, M'Coy (1848), Ann. Nat. 

 Hist. 2nd ser. vol. ii. p. 210. P. rotata, Wright (1851), ib., vol. viii. 

 p. 273. Echinopsis rotata, Fokbes (1854), in Morris's Catalogue, 2nd edit, 

 p. 78. \_P. granulosa, Ag., Cat. Raisonne (1846), Ann. Sc. Nat., 



vol. vi. p. 370. P. Gervillii, Ag., ib., 371. sec. Wright.] 



To the excellent description given by Dr. Wright in the eighth 

 volume of the Annals of Natural History, there is scarcely anything 

 to add ; and as that author and Professor Forbes have both 

 abstained from citing their names, we do not feel justified in as- 

 sociating Tvith this species the other very closely allied forms, viz., 

 P. suhlcBvis and P. aspeva, which Prof Agassiz had first separated 

 in his Echinod. Suisses, and afterwards, in the Catal. Raisonnd, united 

 with P. rotata. Nor would it be proper here to raise a question as 

 to the propriety of uniting Echinopsis with the genus Pedina. 

 The essential character supposed to distinguish the latter genus, viz., 

 having the bosses of the tubercles crenulated, has proved to be a 

 [v. iii.] 5 c 



