PLATE XVII. 



Transverse sections of Ecliinoid K'adioles. 



452. 'Cidarisi trigona, from St. Cassian (Brit. 

 Mus., E lOlOI) ; the flattened face is upper- 

 most ; the axis of the radiole lies at the 

 lower right-hand corner of the figure ; x 30 

 diam 



Pag. 



220 



PaK. 



45.'?. ■Cidarisy linearis, from St. Cassian (Brit. 

 .Mus., E 10102): the position of the axis 

 is marked by a cross ; x 00 diam. . . . 



All figures were drawn from the sections by G. T. Gwili iam, under the Author's direction, at a magnilicafion 

 of 80 and 40 diameters, respcctivelj', and were reduced by photography to the present scale. 



