Dr. T. Wright on the Cassidulidae of the Oolites. 217 



ties N. sinuatus than any other species, having with it affinities 

 in the form and structure of the ambulacra, the narrowness and 

 extent of the anal valley, and the depression of its dorsal surface ; 

 it is distinguished however from N. sinuatus by its oblong circum- 

 ference, produced single inteiarnbulacrum, which is more flat- 

 tened, deflected, and abruptly truncated than in that species. 

 The dorsal surface is likewise more depressed; in fact, the an- 

 gular outline and produced and truncated posterior border sepa- 

 rate N. Solodurinus from all its congeners. 



Locality and stratigraphical range. — This is a rare species ; it 

 was collected by Mr. S. P. Woodward from the upper beds of the 

 Inferior Oolite near Stroud, and to whom we are indebted for the 

 loan of the specimen which has served for the foregoing descrip- 

 tion. We have a broken specimen from the same beds near Sal- 

 perton Tunnel, Great Western Railway : in the Museum of Eco- 

 nomic Geology there is a specimen from the Inferior Oolite of 

 Dorsetshire. Its foreign distribution, according to Agassiz and 

 Desor's ■ Catalogue raisonne/ is " Marn. vesul. Obergoeschen 

 (Jura Soleurois), Egg (Argovie), Poligny (Jura)." 



History. — First figured and described by Agassiz in his ' Echi- 

 nodermes Fossiles de la Suisse/ afterwards identified as a British 

 fossil by Mr. S. P. Woodward, and now described as such for the 

 first time. 



Nucleolites sinuatus, Leske. 



Syn. Clypeus sinuatus, Leske apud Klein, Echinod. p. 157. tab. 12 j 



Parkinson, Organic Remains, vol. iii. pi. 2. fig. 1. 

 Galerites patella, Lamarck? Syst. Animaux, torn. iii. p. 23. no. 14. 

 Clypeus patella, Agassiz, Echin. Fuss. vol. i. p. 36. t. 5. fig. 4-6; 



Agassiz and Desor, Cat. raisonne' des Echinides, A. S. N. torn. vii. 



p. 156. 

 Nucleolites patella, Defrance, Diet. Sc. Nat. torn. xxxv. p. 213 ; Des- 



moulins, Tabl. Synopt. no. 3. p. 354. 

 Echinoclypeus patella, De Blainville, Zoophytologie, p. 189. 



Test orbicular, dorsal surface convex, depressed, sides sloping ; 

 vertex nearly central; ambulacral arese broadly lanceolate, 

 apices closely approximated ; apical disc excentral, behind the 

 vertex, and inclined posteriorly ; anal valley narrowly conical, 

 shallow, with inclining sides extending from the apex to the 

 border ; posterior lobes small ; base concave and undulated ; 

 mouth excentral and pentagonal, margin with five lobes. 



Height I inch and y^ ns > antero-posterior diameter 4 inches 

 and yjjths, transverse diameter 4 inches and T v G ths. 



Description. — This large buckler-shaped Urchin has been long 

 known to palaeontologists from the abundance and fine preser- 

 vation in which its test is found in the lower and middle division 



