Fossil Corals. 



219 



endotheca. The corallites in intemal sections are mostly circular, 

 the majority are of the same size, the walls are thin. The septa 

 include three complete, "well-developed cycles ; between them are 

 some obscure costae, corresponding to the septa of a fourth cycle. 



The specimen agrees essentially with Dana's 0. patula, except 

 that the septa appear more distinct from one another than in his 

 figure (Dana, pi. x, fig. lie), and the columella contains fewer 

 denticles. AYhitelegge ^ has recently recorded the species from 

 Funafuti ; but he gives the corallites as from 5-10 mm. in diameter, 

 and the walls from 2-6 mm. in thickness, with the septa varying 

 from 12-36. He describes the columella as composed of a series 

 of compressed denticles, which agrees with Dana's figure, though 

 the dimensions of the Funafuti coral do not correspond very well. 



Distribution. — Christmas Island. 



Fossil: Pinnacles of the sea-cliff limestone. No. 166. 



Figure. — PI. XIX, Fig. 5. Paii: of a transverse section, x 2 dia^ 

 JSTo. 166. 



Prionastraea magnifica (De Blainville), 1830. 



Favastrea magnifica, De Blainville, 1830. Zooph. : Diet. Sci. nat., vol. Ix,. 



p. 340 ; and 1834, Man. Act., pi. liv, tig. 3. 

 Astrcea ,, Dana, 1848. Zooph, : Expl. Exped. Wilkes, vol. viii, 



p. 231, pi. xii, fig. 3. 

 Frionastrcea ,, EdAvards & Haime, 1850. Mem, Astr,, pt. iii : Ann. Sci.. 



nat., Zool., ser. iii, vol. xii, p. 129. 



Fig. 4. (Xat. size.) 



The collection contains one well-preserved specimen (No. 322) 

 of Frionastrcea, with corallites from 5-9 mm. in dia., a columella 

 2-3 mm. in dia., walls "5 to 1 mm. thick, and three complete and 



1 T. Whitelegge, Funafuti, pt. vi: Mem. Austr. Mus., 1898, No. 3, p. 353. 



