AUSTRALIAN GONIOPOR^. 61 



29. Goniopora North-West Australia (6)3. (PL IV. fig. 2 ; PL XII. fig. 3.) 

 [Holothuria Bank (15 fathoms), colL Bassett-Smith ; British Museum.] 



Description.— CoTollwm explanate, with smooth upper surface, about 4 mm. thick, closely 

 encrusting, edges thin, seldom free, stout epitheca. 



Calicles large up to 5 mm., shallow, polygonal. Walls as thick (1 mm.) raised ridges. 

 The septa rise to the ridge of the wall, and the interseptal loculi may run into one another over 

 the ridge ; sometimes parts of a fourth cycle appear ; as a rule the typical formula can be 

 easily made out (PL IV. fig. 2). The upper edges of the septa are rows of granules or teeth, and 

 slope downwards at various inclinations, sometimes with slight concave curves, towards the 

 centre, where there is a slight fossa ; this is usually, but not always, surrounded by a rosette of 

 pali. The individual pali are often seen to be groups of fused granules at the points of fusion 

 of the septa. At the creeping edges the rows of septal granules run out over the walls to the 

 edges of the projecting epitheca. 



The texture in vertical section is coarsely trabecular. 



This Goniopore bears no superficial resemblance to the last, and yet there is a funda- 

 mental agreement in essential structure which cannot be overlooked. Its shallow calicles, the 

 granular character of the edges of the septa, and the central fossa, suggest, especially where 

 there is no central rosette, that if the structural parts were only on a much smaller scale, the 

 two would be almost indistinguishable from one another. The difference seems in essence 

 to be almost entirely one of size. Cf. Introduction, pp. 23 and 24, on the interdependence 

 between growth-form and type of calicle. See further on the possible serial relationship of 

 this coral with the next two following, p. 63- 



It is noteworthy that this coral comes from a greater depth than the last with the smaller 

 flatter calicles. Two other Gonioporcc with very flat calicles come from great depths : G. China 

 Sea 2, 31 fathoms, G. Maldives 1, 32 fathoms. 



a. Zool. Dept. 1902. 9. 9. 6. 



30. Goniopora North-West Australia (6)4. (PL IV. fig. 3 ; PI. XII. fig. 4.) 

 [Holothuria Bank (15 fathoms), coll. Bassett-Smith ; British Museum.] 



Description. — Corallum encrusting, with convex centre, and edges curving concavely 

 upwards (cf fig. 2, Diagram A, Introduction, p. 24), with slightly projecting and overlapping 

 epitheca. 



Calicles large and open, up to 5 mm., about 1 mm. deep, polygonal on the top, but some- 

 times subcircular near the flattening edges. 



Walls steep and thin but strong, and where simple, a close zigzag is visible under the 

 pocket-lens ; the tips of the septa make the edges bluntly denticulate. The zigzag synapti- 



