ANALYSIS AND DISTRIBUTION OF TYPES OF CALICLE. 179 



G. Great Barrier Reef 2. 



G. Great Barrier Beef 9. Placed also in A (e). 



G. North- West Australia 5. 



G. North- West Australia 6. In parts (see PI. IV. figs. 4 and 5), also /3 



in parts (PI. IV. fig. 6).» 

 G. Philippines 4- On the thinner parts of stock, see also under /3.* 

 Doubtful :— 



G. New Guinea 1. 



G. Great Barrier Reef 3. Tending towards D. 



/9. Walls reduced to a reticulum. 

 G. Great Barrier Reef 6. 

 G. Great Barrier Reef 7, specimens a and c. 

 G. North- West Australia 6. In parts, see also under a* 

 G. Philippines 4- On the thicker parts of the stock, see also under a* 

 G. Singapore 4- 



(b) Walls thin. 



a. Composed of single rows of stout fused trabecular, the tips of which cause 

 the margins to be denticulate ; from below the edges the septa slope very 

 gradually into the depths of the calicle, so that both the pali and the 

 columellar tangle, which in the primitive shallow calicle formed a flat floor, 

 are obscured. 



G. Loyalty Islands 1. 



G. Great Barrier Reef 7, specimen b. 



G. Great Barrier Reef 11. Perhaps also to A (<?). 



Goniopora xd. 



y8. The trabecular not conspicuous as such, and tending with the wall synapti- 

 culee to form smooth lattice-works. The columellar tangle is conspicuous. 



G. Java Sea 1. 



Goniopora x a. 



G. Maldives 4- Walls almost membranous. 



G. Singapore 6. 

 Doubtful :— 



G. Egypt 2. 



7. Walls smooth, like membrane, and perforated with oval pores, closely 

 resembling the walls of Alveopora.\ 



G New Guinea 8 1 g ag • also ^ those of Aheopora 



G. Great Barrier Reef 10 | * v 



G. Moluccas 1. Septa as fine points. 



* These cases show how easily the radial and concentric symmetry of the wall-elements may 

 break down. 



t At the sides of all these colonies the calicles revert to the primitive type with thicker walls ; 

 but for this they would be indistinguishable from true Alveoporce. Other forms with spinous septa, 

 like those of Aheopora, are G. Red Sea 2 and Goniopora xc. The septa of G. Red Sea 4 are filamen- 

 tous, but hardly like those of Alveopora. 



2 A 2 



