94 PERCY SLADEN TRUST EXPEDITION 



and Haime), Fiji (Dana and Quelch), Amboina and Banda (Quelch), Salawatti (Studer), 

 ? East Indies (Dana), and Red Sea (Ehrenberg and Klunzinger). 



6. Favia bertholleti (Valenciennes). (PL 7, fig. 2 ; 22, fig. 7 ; 23, figs. 4 and 6 ; 

 24, fig. 1). 



Parastrea bertholleti, Valenciennes, Mss., Catal. Mus. Paris. 

 1850. Phymastrea valenciennesii, Milne Edwards and Haime, Ann. Sci. Nat., Zool., 3" s^r., x, pi. 9, fig. 3, and xii, 

 p. 124. 



1850. Prionastrea rousseaui (pars), Milne Edwards and Haime, Ann. Sci. Nat., Zool., 3"= s^r., xii, p. 131. 



1851. Prionastrea halicora (pars), Milne Edwards and Haime, Pol. foss. terr. palaeoz., p. 102 (non Astrcea 



halicora, Ehrenberg). 

 1857. Favia bertholleti, Milne Edwards and Haime, Hist. Nat. Corall., ii, p. 431. 

 1857. Phymastrma valenciennesi, Milne Edwards and Haime, Hist. Nat. CoralL, ii, p. 500. 

 1857. Prionastrcea halicora (pars), Milne Edwards and Haime, Hist. Nat. Corall., ii, p. 517. 

 ? 1857. Prionastrcea australensis, Milne Edwards and Haime, Hist. Nat. CoralL, ii, p. 520. 

 1886. Phymastrma aspera, Quelch, Challenger Reports, Reef Corals, Zool., vol. xvi, part xlvi, p. 105, pi. 4, 



figs. 1—16. 



Cor£llluiIl. Massive, convex; corallites longer than broad, usually hexagonal in 

 shape, close together. Calices with diameters about 12 or 13 mm. and 7 or 8 mm. 



Septa usually sloping towards columella, with irregularly toothed edges (about 

 8 teeth), exsert to about "5 mm. 33 — 40 in number (in one corallite 46 septa), 11 — 18 

 meeting columella ; the broader subsidiary septa curving towards and fusing with sides of 

 principal septa near to where the latter meet columella. In some corallites an alternating 

 cycle of rudimentary septa present. Columella usually formed of closely twisted septal 

 trabeculsB, about -^ width of calyx. 



Multiplication by unequal fission. 



Two principal types of corallum may be recognised in this species : (l) in which the 

 adjacent corallite-walls are fused, the inter-calicinal walls thus formed being not more 

 than 1 mm. in thickness, often thinner ; over these the septa are -continuous in arches, 

 the septa being thin ; (2) thicker-looking in which the corallite-walls are distinct, separated 

 on the surface by inter-corallite grooves at the margins of which the exsert ends of the 

 septa stop ; the septa are thicker and rougher. 



Polyps, (l) Both entocoelic and exoccelic tentacles present. (2) Stomodseal ridges 

 thicker than broad, with convex inner surfaces. (3) Nine or ten principal couples of 

 mesenteries. (4) In the stomodasal region of polyp subsidiary couples of mesenteries about 

 twice the number of principal couples. (5) In the same region of polyp entocoelic pleats 

 extending over almost the entire width of principal mesenteries, better developed in their 

 outer half or one-third where the pleats are broader than in any other species of Favia, 

 thin, greatly subdivided, individual ones appearing club-shaped in transverse section ; 

 in inner one-third pleats narrower, thicker, but subdivided to a less extent ; between 

 these two regions pleats often quite narrow or absent and the mesoglsea slightly constricted. 

 (6) Mesenterial endoderm usually thicker in inner pleatal region, and somewhat constricted 

 between the two regions. (7) Convolutions of mesenteries abundant to some distance below 

 stomodeeum but no blocking inter-mesenteric chambers, absent at base of polyps. 



Remarks. A. Polyps. In three large polyps principal couples of mesenteries 

 numbered nine, ten and eleven ; a smaller one had only seven such couples. About 



