CORALS FROM MURRAY, COCOS-KEELING, AND FANNING ISLANDS. I73 



anastomose to form plates."' Branchlets are directed upward on the upper surface, except 

 near and on the periphery, where they are at first horizontal and then curve upward. 

 Lower surface without branchlets, and with only immersed or subimmersed corallites, 

 except on the underside of the peripheral branchlets. A peripheral fragment of a colony 

 has a radial length of 76 mm.; inner end of branch has diameters of 10 by 12 mm.; the radial 

 compression is rather slight. Branchlets simple or bifurcate; height 12 to 15 mm.; diameter 

 of bases, 4 to 5 mm. 



Axial corallites, diameter 2 to 3 mm.; very slightly protuberant, up to about 1.5 mm.; 

 walls, thickness about one-quarter the corallite diameter, composed of costules and con- 

 centric synapticulae; texture loose and friable; costules on outer surface thin and plate- 

 like; septa in 2 well-developed cycles, primaries nearly meeting in the axis; secondaries 

 about half as long; occasionally more than 12 septa. 



Radial corallites immersed or subimmersed on the main branches, diameter 0.6 mm. 

 to about I mm., distance apart slightly greater than the diameter; on the branchlets, 

 except at their bases, prominent and crowded; length on outer surface about 2 mm.; diam- 

 eter at base about i mm.; at tip, about 1.75 mm. The outer wall flares out at the calicular 

 margin and is more or less flattened above; it is reticulate, porous, and costulate; the edge 

 is delicate and friable, but somewhat thickened. There is no recognizable inner wall, 

 except occasionally near the branchlet terminals. The plane of the aperture, {. e., the 

 lip, is nearly at right angles to the surface of the branchlet, but there may be incisions to 

 a slightly lower level against the branchlet. The corallites are labellate, verging toward 

 dimidiate. The outlines of the apertures are elliptical or subcircular. Septa, the 6 prima- 

 ries distinct, directives larger than the others; secondaries rudimentary, obscure, or absent. 



Coenenchyma reticular, porous, echinulate. 



Habitat,etc., Cocos-Keeling Islands. — Dr. Wood Jones makes the following notes: 



"Fragments of a colony found on the barrier flats north of Pulu Bras, where such 



colonies are abundant. They are in pools skirted by Millepora, on the lagoon margin of 



the flats. The branches, while alive, are creamy white; their distal ends and terminal 



polyps pink." 



This specimen has greatly puzzled me, as it does not precisely accord with 

 typical specimens of any of the species with which I have compared it, but it is too 

 similar to A. spicifcra to warrant reference to a different species. It is probably 

 closest to Dana's variety abbreviata, which has "branchlets 6 to 25 mm. long, 

 obtuse at the apex, with scarcely prominent axial corallites." A specimen in the 

 U. S. National Museum, No. 234, from Singapore, U. S. Exploring Expedition, now 

 bears the label "Madrepora spicifera Dana?" but was originally labeled "Madre- 

 pora microclados Ehr. ?" by Dana.- This specimen is undoubtedly the same as 

 the one from Cocos-Keeling Islands, and I am convinced it is Acropora spicifera. 

 The diameter of its axial corallites is from 1.5 to 2 mm., averaging less than in 

 the Cocos-Keeling specimen, and the edges of the corallite lips are not always 

 reflected quite so much as in the latter, but there is a distinct tendency toward 

 flaring and there is some flattening of the edge. 



Distribution. — Indian Ocean from Gulf of Aden to Ceylon, Singapore, and 

 Keeling Islands; Great Barrier Reef; Fiji Islands; Tongatabu. The range is there- 

 fore from the east coast of Africa to Tongatabu. 



Acropora (Lepidocyathus) squamosa (Brook). 

 Plate 72, figures I, 2, 2a, 3, specimen from Murray Island. 

 1893. Madrepora squamosa Brook, Cat. Genus Madrepora, p. 120, plate 20, fig. B. 



A description of a specimen of Acropora squamosa from Murray Island is as 

 follows : 



Corallum corymbose, rising above an expanding base. Height about 17 cm.; greater 

 horizontal diameter about 18 cm.; lesser horizontal diameter about 14 cm. Maximum length 



'From manuscript notes of Dr. Wood Jones. 



'Compare Brook's remarks on Madrepora microclados (Ehr.), Cat. Genus Madrepora, pp. 102, 103. 



