416 Mr. F. M'Coy on some new Mesozoic Radiata. 



ambulacra and the very distinct sulcus connecting the pores of 

 each pair ; the ambulacra of the former species being narrow and 

 the pores unconnected. 



Common in the coralline oolite of Malton. 



Rare in the great oolite of Minchinhampton. 



{Col, University of Cambridge.) 



Nucleolites pyramidalis (M ^Coy) . 



Sp. Char. Base obtusely cordate or rotundato-quadrate, width 

 equalling or slightly exceeding the length, much elevated to a 

 nearly conical apex which is slightly nearer the anterior than 

 the posterior end (length and width 1 inch 2 lines, height 8 

 lines) ; a deep narrow sulcus extends from the vertex to the 

 posterior margin ; petalloid ambulacra of moderate width, the 

 pores of each pair united by a strong sulcus ; upper surface 

 not very tumid, but rather pyramidal, of four slightly flattened 

 sides; profile, anterior end slightly convex, posterior face longer, 

 forming a steeply inclined plane from the pointed vertex to the 

 rounded posterior margin ; granulation of surface very minute 

 and close. 



This resembles the N. clunicularis (Smith sp., Clypeus lobatus, 

 Flem.) in the long, deep, narrow posterior sulcus, extending quite 

 from the vertex ; but is wider and more quadrate, the base having 

 exactly the form of the iV. scutatus (Lamk.) ; from the latter it 

 differs in the strong sulcus uniting the pores as in most of the 

 genus, and from both species it is distinguished by its pointed 

 elevated apex and the straight declivity of the posterior side. 



Common in the cornbrash near Weymouth. 



(Col. University of Cambridge.) 



Nucleolites cequalis (M^Coy). 



Sp. Char. Subquadrate, very much depressed (length 9 lines, 

 width 8i lines, height 4 lines), evenly convex above, very con- 

 cave beneath; vertex central; anal fissure deep, wide, and sharp- 

 edged, extending from the vertex to the margin, which however 

 is scarcely indented; ambulacra very broad, petalloid part with 

 the pores of each pair connected by a deep sulcus ; the two 

 anterior interambulacral spaces are each at the margin only 

 the width of an ambulacral space less than the width of the 

 lateral interambulacral spaces. 



This species is much depressed, but not flattened above ; the 

 ambulacra equal or even slightly exceed those of the N. latifrons 

 (Ag.) in width ; but the species is distinguished from all of the 

 genus by the near equality in size of the interambulacral spaces. 



