PLATE LXXIV. 



HoLASTER sTjBORBicuLARis, Befratice. 



From the Chloritic Marl. 



Fig. 1 a. Upper surface, natural size. My collection. (P. 314.) 



b. Under surface do. 



c. Lateral view do. 



d. Anterior do. do. 



e. Posterior d.% do. 



HoLASTER TRECENSis, Leymerie. 

 From the Lower and Grey Chalk. 



Pig. 2 a. Upper surface, natural size. My collection. (P. 323.) 



b. Under do. do. 



c. Lateral view do. 



d. Anterior do. do. 



e. Posterior border showing the position of the periprocte. 



