MALAY ARCHIPELAOxO GONIOPOR/K. 75 



45. Goniopora Java Sea (4) 1. (Cf. PI. VIII. fig. 4.*) 



[Billiton, coll. Dr. Bolsius ; British Museum.] 



A Goniopora showing the same type of growth as this specimen was named " Goniopora Stokesi, 

 by Milne-Edwards and Haime, Ann. Sci. Nat., xvi. (1851) p. 41 (see next page). 



Description. — Corallum a free hemispherical mass, ca. 5 cm. high and 8 cm. in diameter, 

 with flattened base, the centre of which is often concave, and may show the wrinkled epitheca 

 of the original colony. The living layer extends almost to the base, but there are usually a 

 certain number of edges visible. 



The calicles are large, 4 mm., polygonal, deep, ca. 7 mm. The walls rise to a great height 

 with level top edges ; they are thin, • 5-0 ■ 75 mm., smooth and lattice-like just below their 

 margins, with toothed edges, while in shallower calicles at the edge of the living layer they are 

 thick and reticular. The septa are in three cycles, very thin, and appearing gradually at some 

 distance (2-3 mm.) below the top of the wall, first as minute but not sharply pointed teeth ; 

 their edges describe concave curves before joining the columella. The septal formula appears 

 to be complete and typical, the septa being soon lost in the network of the columella. The 

 columellar tangle is an irregular convex mass of compact reticulum composed of delicate flakes 

 (cf; the thin septa). Here and there, especially in the shallower calicles round the edge, it 

 shows signs of a stellate arrangement of its reticular mass, the rays corresponding with the 

 pali or points of fusion of the septa. 



In texture, there is a great contrast between the solid walls which gradually thicken from 

 their edges downwards and the more delicate intracalicular skeleton built up of the thin septa 

 and the large columellar tangle. Tabula? run through the corallum and are continuous with 

 the epitheca supporting the edges. 



As noted in the Introduction, p. 24, the hemispherical growth-form was one of the 

 simplest modifications of the primitive form of the colony, being obviously due to an increase 

 in depth of the central calicles. 



This coral grows free, the parent having attached itself to some perishable material or to 

 a small loose object. G. Maldives J±, which is of the same type, see next page (8), also grows 

 free. In this Billiton coral, however, the base remains flat and the latest colony completely 

 or almost completely covers all that went before it. 



There are two specimens from Billiton, one in spirit showing the 24 tentacles com- 

 pactly crowded in the bases of the calicles. 



a. (Rolled and worn). Zool. Dept 83. 7. 24. 102. 



b. (In spirit). „ » 83. 7. 27. 7. 



* The figure refers to a on next page. 



L 2 



