4 



BRITISH FOSSILS. 



to be from tlie Coral rag at Calne. Dr. Wright states that he has 

 collected it in the upper beds of the Inferior Oolite at Leckhampton, 

 and that the Rev. P. B. Brodie has found it in the same stratum at 

 Selsley Hill ; also that it is found in the Great Oolite at Minchin- 

 hampton, and at Kiddington in Oxfordshire. 



Explanation of Plate II. 



Eig. 1. Body of the Acrosalenia hemicidarotdes seen from above. 



Pig. 2. The same seen from below, and showing the mouth. 



Fig. 3. An elevated example, seen from the side. 



rig. 4. A specimen in which the dental lantern is preserved. 



!Fig. 5. Apical disk, with its constituent plates and posteal anus. 



Fig. 6. Part of the ambulacral and interambulacral segments, taken from the side. 



Fig. 7. Portions of the same segments from beneath, showing the three-ranked pairs of 



pores in the vicinity of the mouth. 

 Figs. 8. 9. and 10. Primary spines of the natural size. 

 Fig. 11. The base of one of the primary spines magnified. 

 Figs. 12. and 13. Sections of primary spines magnified. 



Fig. 14. Plan of the base of a primary spine, showing the crenulations surrounding the 



socket and a second series above the neck. 

 Fig., 15. A secondary spine highly magnified. 



Fig. IG. One of the interambulacral tubercles seen in profile, elevated on its crenulated 

 boss, the sides of which are slightly excavated and the base surrounded by an 

 areola. 



Fig. 17. Portion of the dental apparatus. 



Edward Forbes. 



October, 1852. 



