rower and higher extremity. This species is only known as a fossil ; in 

 which state the granular surface is generally removed. 



Spatangites subglobosus, Tab. LIV. Fig. 2, 3. This shell is cordated, and 

 on each side, convex and subglobose; with ten striated and bipo- 

 rous ambulacra. Leske adds to these the following characters : 

 Four pores, in the angles of a trapezium on the vertex ; also, in the 

 apex, where the two pores unite, a little pit is impressed. The two 

 neighbouring ambulacra form triangles, the bases of which are in the 

 periphery, and their apices in the vertex. Two rows of pores in the 

 dorsal lacuna reach to the mouth ; and, from the vertex to the anus, 

 a prominent ridge proceeds. Each area is divided by a serrated longi- 

 tudinal suture, and is divided into assulae by transverse lines, slightly 

 arched : the assulae of the larger areae are heptagonal, and those of the 

 less arese are alternately heptagonal and pentagonal. The circumference 

 of the middle of the base is granulated ; but the superior surface is gene- 

 rally so worn, as to show only the traces of the granulae : two fas- 

 ciae, free from granulae, extend from the angles of the mouth towards 

 the anus. The mouth, which is subreniforrn, is near to the grooved 

 margin, and is surrounded by tubercles, disposed in a stellular form. 

 The anus is near to the superior margin of the narrower and undivided 

 extremity. 



*/ 



This description is given more fully, since the figures given by Leske 

 do not accord with that of Lister, to which he refers. The figure given 

 by Walch, Tab. E. iv. Fig. 3, 4, agrees exactly with that of Leske. 



Spatangites ananchytis, Tab. LIU. Fig. 1, 2, Lesk. differs from the pre- 

 ceding, chiefly in its upper part being more conical, its base more flat, 

 and its periphery more oblong. The figure given by Leske, is, from a 

 silicious nucleus ; and the only specimen of this fossil, which I possess, 

 is a spathose nucleus. 



Ananchytis, sen Synochitis, of Mercatus, p. 316, and App. 89, ap- 

 pears to approach much nearer to the form of Spatangites globosus, than 

 to that of this fossil. 



' VOL. III. ' F 



