PLATE XLVII. 



DiscoiDEA CYLiNDRiCA, Lamarck, 1816. 



Fig. 1 a. Large test, lateral view, natural size. M3/ collection. (P. 204.) 

 b. Base of the same, do. 



2 a. Mould showing marginal incisions on the border of the inter-ambulacra. 



b. Mould showing the extension of the same at the base. 

 3. Test wanting anterior single ambulacrum. 



DiscoiDEA MINIMA, Agassiz, 1840. 



Fig. 4 a. Upper surface of a test, natural size. (P. 208.) 



b. Under surface do. do. 



c. Lateral view do. do. 



d. Base of do. magnified. 



e. Apical disc, greatly magnified. 



/. Portion of the inter-ambulacrum, ambulacrum, and poriferous zones, highly 



magnified. 

 g. Upper portion of the same parts, highly magnified. 

 h. The anal plates, highly magnified. 



These figures are copied from M. Cotteau's beautiful plate 1012, figs. 1—7, in the 

 ' Paleontologie Fran9aise,' tom. vii. 



