Fossil Corals. 



219 



endotheca. The corallites in internal 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 costte, 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. H^"), and the columella contains fewer 

 denticles. "VVhitelegge ^ has recently recorded the species fi'om 

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

 and the walls fi-om 2-6 mm. in thickness, with the septa varj-ing 

 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-clrff limestone. !No. 166. 



Figure. — PI. XIX, Fig. 5. Part of a transverse section, x 2 dia. 

 No. 166. 



Prionastrsea magnifica (De Blainville), 1830. 



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



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



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



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



PrionastrcBa ,, Edwards & Haime, 1850. ]\Iem. Astr., pt. iii : Ann. Sci. 



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



Fig. 4. (Xat. size.) 



The collection contains one well-preserved specimen (Xo. 322) 

 of PrionastrcBa, 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. 



