52 MADREPORARIA. 



18 to 20 in number. Septal ridges hardly traceable down the walls in the deeper calicles, 

 and as a rule only begin to appear as teeth some way below the surface, excepting in the 

 shallower lateral calicles, where they are visible as ridges right down the walls. The primaries 

 and a few of the secondaries alone become conspicuous. The columella is a very solid tangle 

 of coarse round threads, from the surface of which arise irregular pali which seem plate-like 

 from above, but are often mere radially arranged filaments, forming the typical rosette. 

 These pali are slight in the deep calicles, but become more and more pronounced in the 

 lateral calicles. One palus is often more prominent than the rest, but the septal formula is 

 too obscured to allow us to make out which it is. The texture of the corallum in section is 

 a very coarse filamentous reticulum, in which, however, the thick walls are prominent. Very 

 delicate tabula?, not numerous, are visible with a pocket lens. 



The single specimen had apparently been split in half at some time from the top of its 

 smooth rounded mass to its base, and the living layer had bent down over the edge of the 

 fracture. The growth-form is provisionally placed in the pulvinate group, see Table III. p. 174, 

 and Introduction, pp. 24 and 26. The specimen differs from most of its congeners in the 

 character of the walls, their edges being composed of single rows of granules. It resembles 

 the last specimen in the conspicuousness of the rosette even in the deep uppermost calicles. 



a. Zool. Dept. 92. 12. 1. 542. 



19. Goniopora Great Barrier Reef a z)5- (PI. II. fig. 6.) 

 [ ? Exact locality, coll. W. Saville-Kent ; British Museum.] 



Description. — Corallum a smooth laterally compressed ridge, with long oval contour, 

 slightly bulging sides, and smooth rounded crest. Thickness of stock, 3-3 • 5 cm. Depth of 

 living layer on the sides, 3-4 cm., but dying irregularly upwards without free projecting edges. 



Calicles deep circular punctures, variable in size up to 2 • 5 mm., and 2 ' 5 deep on the 

 higher parts of the crest. Walls very fenestrated with rather ragged edges, variable in thick- 

 ness but generally thin, with top edges striated by thin bent septal plates conspicuous to the 

 naked eye. No septal points project over the margin, and the wall descends vertically almost 

 entirely devoid of radial ridges (with here and there exceptions). Six symmetrically arranged 

 pali as small points rise high in the calicle near the wall. They are usually thin narrow 

 plates, the bent up teeth of six septa, one or two of another cycle may be developed sufficiently 

 to fuse with them, but the rest, with the tertiaries, remain rudimentary. The interseptal loculi 

 are consequently very large and open. The columellar tangle is light and open. In the vertical 

 section the wall trabecular stand out solid and conspicuous as compared with light intra- 

 calicular reticulum. 



This is only a chip, but it shows the method of growth, somewhat reminding one of the 

 narrow cockscomb-like ridge formed by Q. Great Barrier Reef 2. The skeletal details can 

 be seen in the fig. 6 (PI. II.) to be thin and delicate, and in great contrast with those of the 

 preceding figure. 



a. Zool. Dept. 1902. 9. 9. 4. 



