CORALS FROM MURRAY, COCOS-KEELING, AND FANNING ISLANDS. 93 



septal margins may be greater. The columella may be much compacted and form a cal- 

 careous plug. At one time I thought this variant might be discriminated as a separate 

 species, but I am now convinced that it is only a facies of L. purpurea. 



(3) This is represented by a specimen brought by Dr. Mayer from Murray Island. 

 It has shallow, almost superficial, calices and the septal grouping is not so conspicuous as 

 in typical L. purpurea. (See plate 30, fig. 2.) Astraa pukhra Dana, type No. 74, U. S. 

 Nat. Mus., is like this variant in its septal characters, but has narrower intercorallite areas 

 and deeper calices. 



Because I found certain corallites apparently undergoing fission (op. cit., fig. 

 3#) in the corals I designated as Fain a hawaiiensis, I was misled as to their system- 

 atic affinites and did not recognize them as Vernll's Leptastrea stellulata. Recent 

 comparison with a good suite of specimens of Leptastrea has convinced me that I 

 committed an error and it is here corrected. Comparison of the Hawaiian speci- 

 mens with specimens from the Paumotus, the Philippines, and Cocos-Keeling 

 Islands reveals no characters whereby they can be separated from L. purpurea. 

 Although the outer ends of the larger septa of the former average more exsert 

 than in Indian Ocean specimens, to be described in the next paragraph, any dis- 

 crimination in these characters breaks down by detailed comparison of the two lots, 

 while a specimen from Port Binanga, Philippines, combined both conditions. The 

 most important usual difference between these specimens and L. purpurea consists 

 in their having 6to8 conspicuously large septa, with steep, nearly perpendicular inner 

 margins and the absence or fewness of coarse septal teeth on them; while typical 

 L. purpurea has 12 to 24 septa, more nearly equal in size, with sloping septal mar- 

 gins, and usually with coarse teeth near the columella. But the specific value of 

 the differential characters is invalidated by another specimen from the Hawaiian 

 Islands and an excellent specimen obtained by Mr. Elschner at Fanning Island. 



The four pieces of colonies of this species in the Wood Jones collection from 

 Cocos-Keeling Islands present most interesting variation. On one piece the range 

 in diameter of the calices is from 3.25 mm. to 4.5 by 7 mm.; the thickness of the 

 intercorallite walls ranges from 1 to 4 mm. (see plate II, figs. 3, 3a). One of their 

 conspicuous characters is the steepness of the inner margins of the septa which 

 reach the columella. 



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

 notes: "A common barrier-pool species, which incrusts the surface of rocks. 

 While alive the colony is almost white, the zooids are brown." 



As the specimen of Leptastrea purpurea obtained by Dr. Mayer on Murray 

 Island is not quite typical, the following notes are made on it (plate 30, fig. 2) : 



Corallum massive, irregularly domed above; horizontal diameter near the base 81 by 

 87 mm., height 62 mm. Corallites polygonal, more or less deformed, diameters from 3 to 

 5 mm.; one corallite is 6 mm in diameter. Corallite walls, up to 1.25 mm. across, about 

 1 mm. the average. Calices rather shallow, separated by an intercorallite groove, at which 

 the outer ends of the septa terminate. Fusion of higher to lower cycles of septa not so 

 pronounced as is usual in the species, but fusion into groups does occur. Septal faces very 

 granulate. Columella small, papillate. J. B. Steere obtained in the Southern Philippines a 

 specimen similar to this. A note on the type of Dana's Astrcea pukhra has been made in a 

 preceding paragraph; it and the Philippine specimen are essentially identical. 



Station, Murray Island. — Southeast reef flat, 1,620 to 1,670 feet from shore; 

 water about 16 inches deep at lowest tide; hard bottom. 



Distribution. — Red Sea (Klunzinger and others); Indian Ocean (Gardiner 

 and others); Great Barrier Reef; Southern Philippines (J. B. Steere, collector); 

 Luzon, Philippines (Albatross, 1908); Rotuma and Funafuti (Gardiner, Matthai); 

 Makemo, Paumotus (Albatross, 1899-1900); Fanning Island (Elschner); Hawaiian 

 Islands (as Favia hawaiiensis Vaughan) (W. T. Brigham). 



