PLATE LXXIII. 

 HoLASTER suBGLOBOsus, Leske. 

 From the Lower Chalk. 



Fig. 1 (J. Upper surface, natural size. My collection. (P. 319.) 



b. Under do. do. 



c. Lateral view do. 



d. Posterior border and periprocte. 



e. Anterior do. and auteal sulcus. 

 /. Apical disc, highly magnified. 



y. Ambulacral and interauabulacral plates, and poriferous zones, magnified three 



diameters, showing the regular surface sculpture. 

 h. Ambulacral area and poriferous zones, magnified three times. 

 i. Primary tubercles, with the scrobicular ciixles of granules highly magnified. 



