52 Mr. F. A. Batlier on Eocidaris and 



a fragment, preserving only tlie mamelon, part of the boss, 

 and faint traces of about half the scrobicular ring of tubercles, 

 all apparently tertiary ; there is no trace of any secondary 

 tubercle. Since this agrees with the lecto-holotype in all 

 those characters that are preserved, it may well belong to the 

 same species ; and, if so, it indicates that the platform round 

 the mamelon was slightly hollowed, or, in other words, had a 

 slight parapet ; the mamelon itsidf is much depressed, and has 

 a very short neck, which is not undercut. 



The original of Sandberger^s fig. 2 (our PL I. fig. 3) is 

 too much broken and worn to afford any safe evidence. It 

 may belong to the same species, and at any rate presents 

 no features inconsistent with the preceding account. There 

 is another imperfect plate, unfigured, of much the same 

 character. 



The original of Sandberger's fig, 2 r;? is the proximal end 

 of a primary radicle (our PI. J. fig. 4). The evidence on 

 which tliis is referred to the same species as the three inter- 

 anibulacral plates is merely the occurrence of this and 

 similar fragments in the same stratum as those plates, and the 

 general correspondence in size between its acetabulum and the 

 piimary tubercles of the plates. The shaft is subcylindrical 

 and smooth, but the radiate septa of its microstructure are 

 just visible on the surface as fine longitudinal strise. Its 

 diameters are 3'9 mm. and 3"3 mm. There is no trace of an 

 axial lumen. Ko collerette can be dctf'cted. The annulus 

 swells out gently to dianieters of 4*8 and 3*7 mm., and passes 

 with a slight concave curve into the gently rounded base. 

 The acetabular margin is a smooth raised rim, much worn in 

 the specimen, with outside diameters of 2'9 mm, and 2*1 mm. 

 Since the base has been cracked and is traversed by a vein of 

 calcite, the longer diameters of annulus and acetabulum 

 should be taken as about "O mm. shorter than the measure- 

 ments given. 



The original of Sandberger's fig. 2 c is the proximal 

 portion of a radiole, 14'6 mm. long. It is attached to a 

 fragment of crystalline limestone, and its outer layers are 

 stained, like most of the limestone, a light pinkish red. All 

 the other specimens are of a dull grey colour. In this 

 radiole the shaft appears to have been relatively thinner than 

 in the original of fig. 2 d, being 2'7 mm. in both directions at 

 the distal end, and to have tapered more towards the proximal 

 end, where it has a diameter of 2*3 mm., and then expands 

 again towards the annulus. The base is of the same general 

 character as in fig. 2 d. The chief difference lies in traces of 

 a longitudinal ridging, exceedingly obscure, but apparently 



