E. in. Fig. (), is particularly interesting, in consequence of two of the 

 ambulacra, proceeding from two points, at nearly half an inch distance 

 from each other. The bands formed by three pair arise at the vertex of 

 the shell, the middle one passing straight, and the lateral ones obliquely, 

 to the region of the mouth ; whilst the two posterior pair proceed from 

 a point of the shell just above the anus, and pass round the margin 

 on each side of the anus. The specimen, figured Plate III. Fig. 3, dif- 

 fers from that of Leske and Walch in being larger, and not having its 

 parts so distinctly visible, as to be able to determine the form of the 

 assulae ; which, in the otherwise very correct description of this fossil by 

 M. d'Anhpne, are said to be quadrilateral, whilst in the figure they are 

 depicted pentagonal. Three species appear to exist in a fossil state, in 

 which the ambulacra do not arise from the same point in the vertex of 

 the shell. 



The specimen figured Plate III. Fig. 8, is evidently of the family bris- 

 soides, and might be named Spatangites brissoides Avails. The form is 

 oval; the base concave, and rounded at its margin: in the centre, 

 where the mouth, which is oval, is placed, the ten biporous ambulacra 

 terminate separately : the back is convex ; near the centre of which are 

 four foramina, and the superior lanceolated terminations of each pair of 

 ambulacra : the anus, large and pyriform, is placed on the back, just 

 above the margi n . 



The following species deserve, perhaps, as is ^observed by Leske, to 

 be considered as forming a distinct genus, which might be placed be- 

 tween echinanthus and spatangus. 



Echinitcs pyriformis, Tab. LI. Fig, 5, 6, and Tab. XLIV. Fig. 7, Lesk. 

 The shell is ovate, gibbous, and rather acute at one end ; the base flat. 

 On the back originate five porous, sub-petalous, ambulacral bands, which 

 reach to the periphery : a carinated line ^divides the back of the shell, 

 as it were, in two parts. In the middle of the base is the round^sub- 

 pentagonal mouth, furnished with five prominent lips. Between each 

 of the two prominent lips a double series of pores unite, forming a five- 



