CORALS FROM MURRAY, COCOS-KEELING, AND FANNING ISLANDS. I45 



The corallites are relatively tall and normnlly increase in diameter with upward gro\vth. 

 Height of free portion from 6 to 10 mm. On the periphery of the corallum corallites may 

 be free for 15 mm. Diameters of healthy adult calices: greater, 9 to 10 mm.; lesser, 8.5 to 

 9 mm. Depth, about 7 mm. Stunted calices may be only 6 mm. in diameter and 4 mm. 

 deep. Greater basal diameter of a healthy corallite, 6.5 to 9 mm. 



Wall thin, fragile, and perforate near upper edge, perforations decreasing toward the 

 base but represented by pits with translucent bottoms. Low, equal, somewhat sinuous 

 costse correspond to all septa. Costal profiles flattish or slightly acute, narrow intercostal 

 furrows perforated as has been stated. Minute granulations distributed over the costal 

 surfaces, not confined to the costal summits. 



Septa thin, 4 complete cycles in normal adult calices. Primaries the largest with cor- 

 responding slight elevations on the calicular margins. Their margins are entire, slope 

 inward through a distance of about one-third the diameter of the calice and then fall per- 

 pendicularly to the outer edge of the columella. The secondaries have free portions about 

 two-thirds as wide as the primaries; and by a curve low down in the calice join the columella; 

 The tertiaries are very thin and are usually narrow, sometimes one reaches the columella, 

 but oftener the dendrophylliid septal grouping is indicated. The quaternaries may be 

 rudimentary, represented by low spines, or those next a primary may be considerably 

 developed and fuse to the nearest secondary, thus initiating the arrangement of septa usual 

 in the family. Septal faces with small granulations. Interseptal loculi open and deep. 



Columella compressed; usually, but not invariably, well developed; composed of curled 

 trabeculae; somewhat protuberant in the bottom of the calice. Its length about one-third 

 that of the calice; its width one-sixth to one-fifth that of the calice. 



Habitat and color, Cocos-Keeling Islands. — Dr. F. Wood Jones supplies the 

 following notes: 



"The color is the brown-black of India ink and when living has a greenish fluorescence 

 about the disk. Black when dead. Very similar in habit to C. willeyi and found in com- 

 pany with it. Always in very small masses, 2 or 3 individuals, and I have never seen a 

 growth so large as the specimen of C. trilleyi. By no means abundant. Lives in the darkest 

 holes and is inactive in the light. I have never picked up a wave-cast specimen." 



Dana's type is No. 180 in the U. S. National Museum. The bottom of the 

 calice in the type is narrower and the columella less developed than is usual in 

 the Cocos-Keeling specimens, but there is complete overlapping. The base of this 

 species does not spread as in C. willeyi. The nearest related form known to me is 

 C. manni Verrill, from the Hawaiian Islands, which has much larger calices, and 

 while alive normally has vermillion-red polyps. 



Distribution. — Singapore (Dana's type); Cocos-Keeling Islands. 



Family ACROPORIDiE Verril. 



Genus ASTREOPORA de Blainville. 



1830. Astreofora de Blainville, Dist. Sci. nat., vol. 60, p. 348. 



1849. Astreopora Milne Edwards and Haime, Acad. Sci., Cnmptes rend., p. 258. 



1896. Astraopora Bernard, Cat. Gen. Astr<eopora, Cat. Madreporaria Brit. Mus., vol 2, pp. 77-99. 



Type species: Astrea myriopthalma Lamarck. 

 Bernard records the following species from Australia: 



Species of Astreopora reported by Bernard from Australia. 



