CORALS "FROM FUNAFUTI. 37 



this variation iu rate of growth being doubtless associated with 

 the great size of the pali belonging to the last-named cycle. 

 It is a peculiarity that wliere there is an irregularity of growth 

 leading to the suppression of one of the six spines, it is always 

 associated with the suppression of one of the tertiary septa 

 and its palus together with the septum of the fifth order 

 adjacent to it. 



10^7/ March, 1903. G. C. Bourke.] 



DESCRIPTION OF THE PLATES. 



Plate 5. 



Fig. 1. Lophohelia tenuis, Moseley, enlarged. 



2. Side view of Trocliocycdhus hastatm. 



3. Basal view of the same species. 



4. Enlarged view of the calyx of the same species. 



5. Calyx of a 6-spined individual of the same species. 



6. Lateral view of Trochocyathus vasiformis, n. sp. 



7. Calyx of the same species, showing septa and pali. 



Plate 6. 



Fig. 8. Enlarged view of the upper surface of the youngest specimen of 

 Trochocyathus hastatus, showing thirty-six septa divided into six 

 systems and four orders. The six primary septa are larger than tlie 

 rest but have not yet developed spines, 



8 a. Lateral view of one of the primary septa of the same spcciracu 



showing the horizontally truncated upper edge. 

 9. Enlarged view of the upper siu'face of an older specimen of tlio same 

 species ; the same number of septa is present as in the younger 

 specimen, but conspicuous costal spines are developed in connection 

 with the sis primary septa. 



9 a. The same specimen, natural size. 



10. Ventral view of the same specimen, showing the interseptal loculi 



largely filled up by secondary calcareous deposit. 



11. Enlarged lateral view of a still older specimen, which has been 



somewhat damaged, showing the upgrowtli of the septa to form 

 the calycle of the adult. 



