56 MADREPORARIA. 



I'udimeutary, but can be seen bending round towards the secondaries to make the typical 

 formula. The columellar tangle is large, but loose and open, and only begins to show signs 

 of pall towards the edges, where, in some parts, the calicles are shallower, and show the rosette 

 formation. In other parts the lateral calicles remain ([uite deep, and retain the special 

 characters of the topmost calicles. 



There is only one fragmentary specimen, which is specially interesting because, ha\ang 

 been injured at one time, growth processes are shown which are not often seen. When 

 gathered the living layer was a small encrusting cake with free edges growing on the top of a 

 fragment of a massive growth of unknown shape and size. This large original stock had 

 apparently been killed down, and the new growth started /rom a few of its topmost calicles, as 

 can be seen from a vertical section ; cf. the pulvinate method of growth, Introduction, p. 24, 

 diagram C. But in this case the cushion formation may have been purely accidental. 



The section also shows well-developed tabulae, the first being 6 " 5 mm. below the surface ; 

 this, therefore, was the real depth of the calicle. 



An old label suggests the identification of the specimen with the Gonio^Mva from New 

 Guinea, called " G. pcdunculata " by Quoy and Gaimard. See, however, the remarks on p. 37. 



a. Zool. Dept. 46. 7. 30. 18. 



24. Goniopora Great Barrier Reef (i2)10. (PI. III. fig. 5 ; PI. XII. fig. 2.) 

 [Thursday Island, coll. Saville-Kent; British Museum.] 



Description. — The corallum is a symmetrical, smooth, oval mass, whose edges curl under 

 as far as the base of attachment. 



The calicles, sub-polygonal or circular, are fairly uniform in size, slightly over 2 mm., 

 very deep. The walls are thin, membranous, and perforated by immense round or oval holes, 

 which are very irregular in size and arrangement, so that there are no straight trabeculse in 

 the walls. Their upper edges are very ii-regular, being not only deeply incised by the j^erfora- 

 tions, but the intervening denticulations are irregularly thickened towards one calicle or the 

 other by the rudiments of the septa. The three cycles distinct as rows of long irregular 

 filamentous spikes projecting from the walls, all of them very rudimentary until deep down in 

 the base of the fossa, where the radial symmetry is obscured by their bendings and fusions. 

 The secondaries are less developed than the primaries, and the tertiaries persist as rudiments. 

 The fusions of the septa are too irregular to show the typical septal formula. The tangle 

 resulting from the meetings and fusions of the septa can hardly be said, except in the shallow 

 lateral calicles, to condense into any definite axial structure, but to be loosely spread over the 

 whole base, with a few large irregular interseptal loculi around the wall not radially arranged. 

 In the shallower lateral calicles large smooth pali-form knobs arise almost to the top of the 

 wall, and form conspicuous star-like groups in the midst of which the columella, though of 

 stouter threads, persists as an open reticulum. 



