PLATE 34 A. 



Fig. 1. 513. 3. ASTROCERIUM PYRIFORME. ( Pag. 123.) 



1 a. A spheroidal form of this species. 



1 6. A turbinate form, the cells increasing rapidly from a narrow base. 



1 c. An irregular turbinate form of larger size. 



1 d. A portion enlarged, showing the internal structure of the cells. 



1 e. An enlarged portion from the inner walls of the cells, showing tlie granulated or papillose surface from 



the bases of the spiniform rays. 



Fig. 2, 3. 514. 4. Astrocerium constrictum. (Pag. 123.) 



2 a. A fragment of a hemispheric mass, natural size. 



2 6. A portion of the same enlarged, showing the constricted growth at intervals. 



2 c. A transverse section of the same enlarged, showing the stellate character of the ends of the columns. 



3 a. A small hemispheric form of this species. 



8 b. The base of the same, showing its mode of growth upon the valve of an Atryf.*. 



3 c. Profile view, showing the form and elevation. 



3 d. The base of a larger specimen, which commenced its growth upon a small shell. 



3 e. A portion of the surface enlarged, showing the form and apparent stellate character of the cells. 



