PLATE LV. 



rif!. 



1. Cellepoka DicHOTOMA, p. 403; adult zooecia. 



2. , yoimger cells from the margin of 



the colony. 



3-6.  , nat. size^ showing the varieties of 



habit. 



7. , var. ATTENUATAj rather young cells. 



8. , single cell and spatulate avicula- 



rium. 



9. - — — , section of the stem. 



10. , nat. size. 



11,12,11. Cellepora Costazu, p. 411 j normal form. 

 13. ■, var. a (tubulosa). 



