PLATE 11. 



Crista. 



Figure 1. — Crisia eburnea, var. laxa, 



la, part of the zoarium, front, 



„ 2. — Crisia cylindrica, 



2a, lower portion of a young zoarium, 



„ 3. — Crisia denticulata, 



3a, front ; 36, ooecium, 



„ 4. — Crisia cylindrica, 



4a, older part of zoarium, front, 



,, 5. — Crisia conferta, . 



5a, part of the zoarium, with ooecium, 



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