Plate 23 



Figs. 1-3. Petralia japonica Busk, 1884 (p. 254). 



1. Surface of unilamellar zoarium, X20, with ovieelled and ordinary 



zooecia. 



2. Interior of zooecia, X20. The two lateral condyles arc visible and an 



operculum is in place. 



3. Inferior side of zoarium, X20, showing the perforated area and the 



numerous radicular pores. 



D. 5311. China Sea, vicinity of Hong Kong. 

 4-9. Petraliella crassocirca, new species (p. 257). 



4. Unilamellar specimen, ■ 20, showing the avicularia and the details of 



the bipartite shield. 



D. 5579. Darvel Hay, Borneo. 



5. Interior, X20, exhibiting the two condyles and the form of the tremo- 



pores. 



6. Zooecial surface, X20, showing the ovicell and its structure. 



D. 5147. Sulade Island. 



7. Inferior side of specimen shown by Figure 4. 



D. 5579. Darvel Bay, Borneo. 



8. Inferior side, X20, of a specimen showing the perforated area closed 



by a chitinous membrane. 



9. Microstructure of the frontal, X85. 



D. 5102. Tinagta Island. 

 10, 11. Petraliella giyantca, new species (p. 258). 



10. Unilamellar zoarium, -20, with zooecia. hearing trace of an ovicell and 



the salient avicularia. 



I). 5102. Tinagta Island. 



11. Zooecia, ■ 20, with small avicularia. 



I). 5579. Darvel Bay, Borneo. 



(590) 



