268 MB. J. S. GAUDIlfEll ON tHE PEEPOBATE [Apr. 5, 



seem to me to be formed from such by the edges creeping out by 

 budding-off calices regular!}^ in lines. Then thickening takes place 

 by the dii-ect upward growth of the cells and budding in the cell- 

 walls, where thi-ee or more calices meet. 



It is interesting to note that no branching-forms were obtained 

 at Funafuti or Rotuma, and that no colonies were found on the 

 outer reefs proper of these islands. 



1. PoEiTES ALTEOLATA Edwards & Haime. (Plate XXIV. 

 fig. la.) 



Porites alveolata Edwards & Haime, Cor. iii. p. 178. 



I have referred a small, closely incrusting colony to this species. 

 Its calices are small, 8-9 in 1 cm., generally considerably deeper 

 than broad, with relatively thick walls covered with rough, some- 

 what granular spines. The septa are 12 in number, thin, and 

 little projecting, with almost perpendicular edges. In front of 

 and joined below to the primaries are 4-6 thick, rough, but little 

 projecting paU. Deeper in the calices both these and the septa 

 seem to be united by a ring of corallum, leaving in the centre, as 

 there is no columella, an extremely deep axial fossa. 



Eotuma; boatr-channel. 



2. Porites tieidis, n. sp. (Plate XXIV. figs. 1 6, 2.) 



Corallum massive, uneven, irregularly monticulose, incrusting at 

 the base ; growing edges thin, generally not more than 2-3 mm. 

 in thickness, closely covered by the epitheca, and often free for 

 5-10 mm. 



Calices deep (1 mm.), polygonal, generally very regular in size, 

 1*5-2 mm. in diameter, or about 6 in 1 cm. ; in the deeper valleys 

 smaller and irregular, often elongate. Cell-walls very thin on the 

 surface, but much thicker below, being at the base of the calice 

 about a third its diameter in breadth ; where 3-4 calices meet 

 they are often much thicker, and fresh calices are budded-off. 

 Upper edges of the walls covered with low, blunt, rough spines, 

 and just within the calice, apparently attached to its wall, there 

 are 12 thick, rough, projecting spines, corresponding to the septa 

 which arise deeper. Secondary and primary septa often fused at 

 their edges, and fused to the latter are 4-6 generally thin, blunt, 

 rough, and little projecting pali. Lower in the calice a ring of 

 corallum is often seen, joining all the edges of the septa together ; 

 from this strands of corallum run to join in the centre of the axial 

 fossa, giving rise apparently to the small blunt columella, which is 

 almost as prominent as the pali. 



In section the corallum is seen to be dense and heavy, the walls 

 of the cells thick and compact, with a very regular, close, palisade 

 arrangement across the cells below the base of the columella. 



Var. APALATA. (Plate XXIV. fig. 1 c.) 



The calices are generally less deep than in the type, and have 

 rather thicker walls. The septa are 12 in number, generally less 



