PLAÏE XV. 



Fig. I — 7. Amphiroa crassa Lamx. 



Fig. 1, 4. f. typica. nat. size. 



Fig. 2. f. Godeffroyi. nat. size. 



Fig. 3. f. minuta. nat. size. 



Fig. 5. Node between two joints. The cortical layer has split all around the node. 30 /,. 



Fig. 6. Node entirely surrounded by the calcified cortical layer. 30 /,. 



Fig. 7. Cells of central strand, showing the small pores in the longitudinal walls. 405 /,. 

 Fig. 8. Node of Arthrocardia cretacea (Post. et Rupr.). *'ƒ,. 



Fig. 9. Node and branches of Metagonwlitlwn stelligerum. The branches spring from the node. 30 /,. 

 Fig. 10. Section through node of Metagoniolltlion graniferum. '''/,. 

 Fig. il. Longitudinal section through apex of branch of Metagoniolltlion charoldes. The small cells indicate 



the future node. 95 /,. 

 Fig. 12. Young top of Metagoniolltlion graniferum showing the thick mucilaginous layer covering the top; 



in this layer slight striae were visible. 47 /,. 

 Fig. 13. Metagoniolltlion stelligerum. Node with three branches. *'/,. 



Fig. 14. Cells of central strand of Metagoniolltlion, showing the big, thin places in the longitudinal walls. 405 / r 

 Fig. 15. Lithothrix aspergillum Gray. Longitudinal section through top of frond. *'/,. 

 Fig. 16 — 17. Lltharthrou (Amphiroa) australls. 



Fig. 16. Joints of young fronds. 3 /,. 



Fig. 17. Longitudinal section through frond. " 5 /j- 



