AUSTRALIAN GONIOPORiE. 51 



of septa separated by a median furrow may appear. The 24 septa appear uniformly developed 

 as slight knobs round the margin and descend as inconspicuous ridges into the fossa, only 

 becoming differentiated in its base, where the typical septal formula can be easily seen. 

 Their fusions result in an irregular granular axial tangle, from which long, thin, jagged points 

 tower up as pali, often almost to the aperture of the calicle. In the shallow lateral calicles 

 columella and pali solidify into a large group of G smooth coarse glassy grains nearly filling 

 the base, each grain being obviously the point of fusion of either 3 or 4 septa. The 24 

 interseptal loculi are conspicuous around the columella, but are greatly shortened by the size 

 of the rosette in the shallower calicles. 



The calicles figured are from the side about half-way down, where the tall spike-like pali 

 are passing into the coarser granules of the lowest calicles. 



The single specimen forms a nearly globular mass which has enveloped the tips of some 

 branches of a Mussa. It is nearly 10 cm. in diameter, but rather light owing to the very 

 open character of its skeleton. The upper surface is extremely friable. The lower edges 

 nowhere hang free, but closely adhere, running in between the calicles of the Mussa. The 

 specimen closely resembles the Mad. intersepta Esper, see below, Goniopora xg, p. 160. For a 

 somewhat similar method of growth, by the close investment of projections from the sub- 

 stratum, see G. Great Barrier Reef 7, specimen b, PI. XII. fig. 1. The extraordinary friability 

 of the top of the stock, owing to the extreme fenestration of the septa, and the tall jagged 

 spike-like denticulations of the walls, coupled with the method of growth, are the chief features 

 of this coral. 



As in the case of G. Tonga Islands 8, specimen a, we are inclined to ascribe this very 

 porous and friable skeleton to rapid growth. The stock is very light for its size. We may 

 note as a further interesting feature of this coral that the rosette formation is especially con- 

 spicuous even in the uppermost calicles, in which it is usually obscured, that is, when the 

 calicles are deep. In the lateral calicles the rosette is by far the most striking structural 

 feature. 



a, Zool. Dept. 92. 12. 1. 419. 



18. Goniopora Great Barrier Reef Q2)4. (PI. II. fig. 5.) 

 [Exact locality not recorded, coll. W. Saville-Kent ; British Museum.] 



Description. — Corallum with smooth rounded surface, and with hardly any free edges, 

 the living layer being bulged out all round the specimen, which is unfortunately only a 

 fragment. 



Calicles 3 ■ 5-4 mm., subpolygoual and deep, 3-3 ■ 5 mm. The walls are thin and built of 

 straight rows of stout nodulated trabecular, the tips of which appear like grains in single rows 

 along the edges of the walls. The perforations in the wall are fairly regular oval apertures, 

 in vertical series, making the otherwise stout walls a somewhat open lattice-work. The 

 granules forming the edges of the thicker walls of the lateral calicles are large and coarse, 



h 2 



