Explanation of Plate 



Fig?. 1-12, Corbitella speciosa (Q. and Gr.). 



Figs. 1-2. A large and a small dermalia. 150 x . 



Fig. 3. A smooth microxyhexactin from the parenchyma. 300 x . 



Fig. 4. A gastralia. 150 x . 



Figs. 5-S. Small, plump-looking spicules of various shapes and dimensions . 



from the parenchyma. 150 x . 

 Fig. {). Two spin)' microxyhexactins from the parenchyma. 300 x . 

 Fig. 10. A discohexaster with 2 or 3 terminals to each principal. 300 x . 

 Fig. 11. A discohemihexaster. 300 x . 

 Fig. 12. A small discohexaster found only once. 440 x . 



Figs. 13-15, Corbitella elegam (Maksh.). 



Fig. 13. A hexactinose discohexaster. 300 x . 

 14, 15. Dermalia. 150 x. 



Figs. 16-23, Heterotella corbicula (Bowerb.). 



All from Specimen A. 



Fig. 16. A marginalia. 100 x . 

 Figs. 17-19. Dermalia. 150 x. 

 Figs. 20-23. Spiny microhexactins. 300 x . 



