BRITISH FOSSILS. 



Decade I. Plate IX. 



NUCLEOLITES CLUNICULARIS. 



[Genus NUCLEOLITES. Lamarck (sub-kingdom Radiata. Class Echinodermata. 

 Order Echinidse. Family Clypeasteridse.) Body oval or cordate, more or less tumid, 

 sometimes much depressed ; ambulacra dorsally petaloid ; anus supra-marginal ; mouth 

 sub-central.] 



[Sub-genus Nucleolites. Anus superior, in a furrow ; mouth not surrounded by tubercles.] 



Synonyms. Clypeus clunicularis, Phillips, Geol. York, part 1, p. 115. 

 Nucleolites clunicularis, Bronn, Lethaea Geognost., p. 282. 



Diagnosis. N. amhitu suborbiculari, subquadrato, antice rotundato, 

 postice bilobato; dorso convexo, apice subcentrali, vertice apicali, postice 

 declivente; ambulacris anguste lanceolatis ; sulco anali prof undo, lanceolato, 

 apiculato, ad apicem angustato, lobis posterioribus vix tumidis ; ventre 

 concavo. 



Var. a. Major, subdepressa^ lata, lateribus tumidiusculis. — Spatangus 

 depressus, Leske, ap. Klein, p. 238, t. 51, f. 1, 2 (copied in Enc. Meth., pi. 

 157, f. 5, 6). Nucleolites scutata, Lamarck, An. s. Vert. 3, p. 36. De- 

 FRANCE, Diet. Sc. Nat., vol. XXXV., p. 213. N. clunicularis, b. Bronn. 

 Leth.j p. 283. N. scutatus, Agassiz, Echin. Suiss. p. 45, pi. 7, f. 19-21. 



Yar. /3. Minor et media, convexa, lateribus tumidiusculis. — Nucleolites 

 gracilis, Agassiz, Echin. Suiss. p. 44, pi. 7, f. 10-12? 



Var. y. Media, pyramidata, lateribus planiusculis. — N. Sowerbii, 

 Defrance, Diet. Sc. Nat., vol. xxxv., p. 213. N. pyramidatus, M'Coy, 

 (confirmat. in lit.), Ann. Nat. Hist., 2nd ser., vol. ii., p. 416, Dec. 1848. 

 [Variety figured in our plate.] 



The name clunicularis, as applied to a fossil sea-urchin, has its origin 

 with Llhwyd, who, in his " Lithophylacii Britannici Ichnographia'' 

 (1699), describes " Echini tes clunicularis. Echinites e lapide selenite, 

 quinis radiis e duplice serie trans versarum lineolarum conflatis," and 

 refers to certain figures in the works of Lister and Plot. The figure in 

 Plot (''History of Oxfordshire," tab. 11, f. 12) represents a body which 

 is possibly Nucleolites clunicularis of Phillips, but so badly, that no anal 

 furrow, or anus, is delineated. This figure is referred to by Lister, 

 in his book " De Lapidibus Turbinatis (1678), cap. 11, titulus xxvi./' 

 with a query whether it be identical with his own figure, t. 7, p. 26, 

 [r. ix.] K 



