FROM THE UPPER GREENSAND. • 101 



extending at the base between the primaries and the poriferous zones, and by its narrow 

 peristome sunk in a deep depression ; a careful comparison of typical specimens of Diadema 

 Michelini, Ag., from the Upper Greensand of Villers-sur-Mer, Calvados, kindly sent by 

 M. Michelin, has satisfied me that Diadema Bond, Eorb., is identical with D. Michelini; 

 and that P. Benettice, Eorb. (PI. XV, fig. 2), both as regards its general form, the number, 

 disposition, and character of its primary and secondary tubercles, the sraallness of the 

 mouth-opening, situated in a deep depression, and the equal lobes of the peristome, is 

 identical with some forms of P. Michelini oi\\\^ same size. 



Locality and Straii graphical Position. — This species is very common in the Upper 

 Greensand near Warminster ; the smaller forms arc very closely allied to the Diadema 

 BenetticB, Forb., the larger to the D. Bonei, Eorb. ; it has likewise been found in the same 

 formation at Durdle Cove, Dorset. 



Foreign Localities. — It has been collected from the Etage Ccnomanien of France ( = 

 Upper Greensand) at Villers-sur-Mer, Cauville, Vaches-Noires, Saint-Jouin (Calvados) ; 

 Octeville (Manche) ; Fecamp, Orcher, Le Havre, Rouen (Mont-St.-Catherine), Seine-Infer. ; 

 Vimoatiers, Grace (Orne) ; Prcsagny (Eure). 



PsEUDODiADEMA Benetti^, Forbcs. PL XV, figs. 2, a—f. 



Diadema Benetti.e, Forbes. Morris, Cat. Brit. Foss., 2nd cd., p. 7C, 1854. 



— — Woodvjard. Memoirs of tlie Gcol. Siirv., Decade V, p. 7, 



1856. 

 PsECDODiADEMA Benetti.s, Besor. Synopsis des Echinides fossiles, p. 72, 1858. 



— — Bvjardin et Hvpi. Hist. Nat. des Zoophytes, EcLino- 



dermes, p. 499, 18G2. 



— Michelini, Colteau (pars). Paleontologie Fran9aise, Terrain Cretace, 



p. 476, 1864. 



Test circular, inflated, depressed; ambulacral areas wide, with two rows of tubercles 

 15 in each, separated by a double row of minute granides; inter-ambulacral areas with 

 two rows of primary tubercles, 14 in each; separated by a wide median space, unequally 

 granulated ; miliary zone smooth above ; a few small secondary tubercles at the base ; 

 primary tubercles of both areas nearly of the same size. Peristome very small, deeply 

 sunk in a concave depression ; discal aperture large and pentagonal. 



Dimensions. — Transverse diameter one inch ; height four tenths of an inch. 



Description. — This beautiful little Urchin was formerly considered to be the Diadema 

 ornatum, Goldf., and recorded as such in the first edition of jMorris's ' Catalogue of 

 British Fossils.' It was subsequently considered by Professor Forbes to be a distinct 

 species, and in the second edition of that work was dedicated by him to the late Miss 



