Plate II. 



Placosoma 'paradictynm Ij. Pp. 2-19. 



Fig. 1, A dermalia fiMm the frontal lattice, with greatly elongated proximal 



ray. 1.50 x . 

 Fig. 2. A dermalia from the frontal lattice, with short proximal ray. 



Lateral view. 1.50 x . 

 Fig. 3. A gastralia from the gastral cavity inside the primary or main 



osciilum. 1,50 X . 

 Fig. 4. A raediiim-sized hexactinose discohexaster from a hypodermal beam 



of the frontal lattice. 300 x . 

 Figp. .5, G. Hemihexactinose discohexast( rs of occasional occurrence. From 



the back side of the sponge. 300 x . 

 Fig. 7. A large hexactinose discohexaster, from the same side. 300 x . 

 Fig, 8. A hexactinose codonliexaster from the main gastral surface. 300 x . 

 Fig. 9. A normally developed discohexaster, occasionally fourni together 



with the large spherical form of fig. 11. From the back side. 



300 x . 

 Fig. 10. Another occasional form of discohexaster (codonhexaster) from the 



same side. 300 x . 

 Fig. 11. A large, spherical discohexaster from the same side. 300 x. 

 Fig. 12. A portion of the same, showing the central parts. 300 x. 

 Fig. 13. A small portion of the frontal latti(H\ Above, the dermal lat- 

 ticework. Below, the hypodermal beam. .50 x . 

 Fig. 14. Dermal surface of the back. 50 x . 



Fig. 1.5. A small portion of septum from the choanosome. ;50 x . 

 Fig. 16. Surface of the main gastral cavitv. 50 x. 



