PLATE III a. 

 CiDARis DissiMiLis, Fovbes, 1854. 



From the Grey Chalk. 



Fig. 



1 a. Upper surface of the test, with spmes attached, natural size, from the late Mr. 



Taylor's collection, now in the British Museum, p. 46. 



h. Portion of an inter-ambulacral spine of this 'species, magnified several diameters. 

 British Museum. 



2 a. Test and spines, upper surface, natural size, belonging to the Rev. T. Wiltshire, F.G.S. 

 h. Test and spines, under surface, natm-al size, ditto, ditto. 



c. Penultimate inter-ambulacral plate from the upper part of the column, showing the 



obsolete tubercle and areola. 



d. Inter-ambidacral spine, natural size. 



e. Portion of the stem, neck, and head, of the same spine, magnified several times. 

 /'. Portion of another smaller spine, magnified. 



ff. Ambulacral spines, natural size and magnified. 



3 & 4. Inter-ambulacral spines, natural size. Rev. T. Wiltshire's cabinet. 

 5. A smaU test and spine, natural size, ditto, ditto. 



