PLATE XX. 



Figs. 1-3. — Acanthocladium huxleyi. Magnified details. 



Fig. 1. — Portion of a phylactocarp with a gonangium. The points from which the other 

 gonangia had been detached are seen close to the bases of the costas. 



Fig. 2. — Portion of a hydrocladium with two hydrothecse ; lateral view. 



Fig. 3. — Distal extremity of a branch, showing the spine-like appendages by which the 

 hydrocladia are here replaced. 



Figs. 4-6. — Aglao2)henia macgillivrayi. Magnified details. 



Fig. 4. — Portion of a hydrocladium ; lateral view. 



) 

 Fig. ,'5. — Same ; front view. 



Fig. fi.— Corbula. 



