INDIAN OCEAN GONIOPOR^l 87 



parts of the mass, the surface is quite smooth, the walls being not raised at all ; in others the 

 peripheral septal granules get very large, coarse and crowded, and gradually rise into a slight 

 thick wall-ridge; in others, again, the wall-ridge rises rather suddenly, and the wall is 

 thick, smooth-topped, and nearly flat, its component granules being large and crowded. The 

 typical palic formula can be made out, though somewhat obscured. It consists of the rather 

 larger frosted granules rising where the septa fuse together. The directive septa with the 

 central granule frequently divide the calicles conspicuously into symmetrical halves. Fig. 1 

 shows the calicles of a stock with walls slightly raised. 



The method of growtli here is peculiar. We have thin encrusting Goniopores in G. China 

 Sea 3 and 3, and also Goniopora JY. W. Australia Q and 5, and they all show \\\W\ slight 

 variations the same type of calicle, the septa appearing to be rows of granules. 



In the present case the method of growth is peculiar, for the colonies keep through- 

 out the same smooth curvature of surface. This, as the colonies break up, necessarily results 

 in a lobulate reniform mass, all the lobules showing a similar curvature. 



We are here again confronted with the prolilem as to the relation of growtli-form to the 

 shape of the calicle. Did the shallow calicle with the rows of granules for septa start this 

 encrusting form of colony, or did the early form in which the colony was able to grow fix the 

 character of the calicles ? It is worth noting that on this specimen the calicles vary according 

 to the position on the stock of the colonies to which they respectively belong. 



The dimensions of the single specimen are 15 cm. long and 8-9 liigh, and there are 

 twelve colonies on it of all sizes from 1 • 5 cm. in diameter to long straggling strips 8 cm. long- 



57. Goniopora Maldives (4)2. (PI. VII. figs. 2 and 3 ; PI. XIII. fig. 7.) 

 [Hululu, coll. Gardiner ; Cambridge University Museum and British Museum.] 



Description. — Corallum rises into short, tMck, angular, rather flat-topped columns, slowly 

 increasing in thickness as they rise, and with smooth flattened sides. The living layer 

 descends to various depths, from 5-6 cm., sometimes even reaching 9 cm. 



The calicles on the flattened, slightly convex and irregularly wavy top (fig. 2), are all of 

 the same pattern, some 3 mm. across, 2-3 mm. deep, conical, crowded, but all as if breaking 

 through an extremely friable, ragged, laminate reticulum. The walls are thin and membranous, 

 very porous, with large openings, and, consequently, frequently incomplete at the edges; 

 they are hardly conspicuous enough to show any definite zigzag or straight course of their 

 own. The laminate septa form the chief element in the walls, and are so incised and porous 

 as to appeiir quite ragged, while the obscuration of their radial symmetry adds to this efi"ect. 

 They begin to project in irregular numbers just below the margin, but their deeply incised 

 edges merely send sharp or forking tongues into the fossa, which there twist and bend about, 

 meeting and fusing deep down in the calicle. 



The calicles at the sides have a very different character (fig. 3), which reaches a climax 

 on the lowest strips of the living layer, where tliey are frequently 5 mm. across, almost flush 



