4 



BRITISH FOSSILS. 



Chalk Marl itself, and more rarely in the Lower Chalk. It occurs 

 in all the English counties where these beds are found. It has 

 not been observed in Ireland. 



Explanation of Plate VII. 



Pigs. 1. 2. 3. and 4. Views of an example of the normal form. The specimen selected 

 is from the chloritic marl of Dorsetshire. 



rigs. 5. 6. 7. and 8. Outlines of different varieties from the chalk marl, 

 rig. 9. The apical disk. 



Fig. 10. Ambulacral and interambulacral plates from the upper portions of their 

 segments. 



!Fig. 11. A tubercle and granules from the upper surface. 

 Pig. 12. A tubercle and granules from the lower surface. 



Edward Forbes. 



October, 1852. 



