31 



above the margin. The shell is remarkably firm and thick ; and its 

 colour, as well as that of the calcareous matter with which it is filled, is 

 a light yellow. It is figured by Walch, Tab. E. iv. No. 1 and 2 ; by 

 Klein, Tab. xxv. ; and by Faujas St. Fond, Histoire Naturelle de la Mon- 

 tagne de St. Pierre, PI. xxix. , 



A faithful representation of this fossil is given Plate III, Fig. 4 and 5. 

 This fossil has been sometimes termed Spatangns Mosa, from the circum- 

 stance of the Meuse laving the hills at the foot of St. Peter's mountain, 

 where it is found. 



Spatangus purpurais, Tab. XLIII. 3, 4, 5, Tab. XLV. 5, Lesk. The recent 

 shell, as figured by Leske, Tab. XLIII. 3, 4, 5, Tab. XLV. 5, but particularly 

 in the latter plate, which represents the back of the shell, appears to 

 agree exactly with the fossil which I have represented Plate III. Fig. 9, 

 which I purchased from Mr. Forster's collection, and which I believe 

 to be a Maltese fossil. 



This fossil is of a subangular cordated ovate shape. Four large pores, 4 

 near to each other, form, as it were, the centre in the vertex, which is 

 rather flat ; and at which four ambulacra, and a deep and wide dorsal 

 groove, concentre. Each of the four ambulacra is of a lanceolate 

 petalloidal figure, formed by two bending bands of a double row of 

 oblong pores, each pair of which is connected by an oblique furrow. 

 The small spaces, or areae, contained within the ambulacra, appear to 

 have been beset with very minute pores and tubercula ; and a serrated 

 line, passing through their centre, connects two rows of* hexagonal 

 assulge. The remaining part of the superior surface is divided into five 

 large areae. In the anterior part is the dorsal groove, wide, rounded, and 

 deep, passing from the base to the vertex, forming a semicircular notch 

 in the margin, and narrowing as it rises. On each side of the dorsal 

 groove is a raised triangular flat surface, bordered by two tuberous 

 ridges, which, rising from the vertex, proceed downwards ; the tubera 

 nlarging, to the margin, and slight transverse risings connecting the 

 opposite tubercles. Similar raised surfaces descend through each of the 



