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



Distribution. — Red Sea; Indian Ocean. Closely related species widely distrib- 

 uted in the Pacific, but A. scherzeriana has not yet been positively identified in that 

 region. 



Acropora (Tylopora) geinmifera (Brook). 



Plate 77, figures I, la, 2, 2a, 3, 3a, specimens from Murray Island. 

 1893. Madrepora gemmifera Brook, Cat. Genus Madrepora, p. 142, plate 31. 



Dr. Mayer obtained a fair suite of specimens of this species, which shows a 

 wide range of variation. A selected series is illustrated and the following annota- 

 tions are made on the specimens according to their habitat: 



Plate 77, figures i, \a, are views of a specimen from 6 miles east by north of 

 Murray Island, inner side of the reef patch, water 3 to 4 feet deep, coral-rock bottom. 

 This was a healthy colony. It is especially characterized by the prominent, com- 

 pressed, nariform, gutter-shaped, or dimidiate radial corallites of the upper surface. 

 Because of the pronounced compression of the radial corallites, I at first doubted 

 its being A. gemmifera, but careful comparison with the specimen next to be con- 

 sidered convinced me that they are variants of the same species. 



Plate 77, figures 2, 20, represent a specimen from the same locality. It is very 

 similar to Brook's type. Radial corallites are less prominent and less compressed 

 than in the first-mentioned specimen, but the two intergrade. This variant is repre- 

 sented by a second specimen from the same station. 



Plate 77, figures 3,3a, illustrate a specimen from the inner edge of one of the 

 outer reef patches of the Great Barrier Reef, 6 miles east of Murray Island, water 

 about 4 feet deep, in a strong current and subject to breakers. The base is over- 

 grown by Lithothamnion, which extends up many branches. The branches are 

 reduced in diameter, and the radial corallites project very slightly or not at all, 

 except in one protected place on the periphery. 



Two stunted specimens, one dead, the other nearly dead, were collected on 

 the Lithothamnion ridge of Murray Island. 



Distribution. — Great Barrier Reef, Australia. 



The species is very closely related to A. scherzeriana. The most important 

 differences are the smaller axial corallites, the more persistent presence of small, 

 scale-like corallites on the larger radial corallites, and a larger number of more 

 prominent proliferous radial corallites in A. gemmifera. Brook has given a good 

 description, which needs to be supplemented by the foregoing notes under the 

 first and third variant. 



Acropora (Tylopora) ocellata (Klunzinger) var. 

 Tlate 76, figures 3, 3a, 3^, specimen from Cocos-Keeling Islands. 



1879. Madrepora ocellata Klunzinger, Korall. Roth. Meer., pt. 2, p. 9, plate 1, fig. 7; plate 4, fig. 14; 



plate 9, fig. 5. 

 1893. Madrepora ocellata Brook, Cat. Genus Madrepora, p. 148. 



1906. Acropora ocellata von Marenzeller, Denksch. k. k. Akad. Wiss. Wien, vol. 80, p. 26, plate 18, 



fig. 81a; plate 24, fig. 81. 



1907. Madrepora pulchra Wood Jones, Proc. Zool. Soc. London for 1907, p. 531, text-fig. 154, plate 27, fig. ic. 

 1910. Madrepora pulchra Wood Jones, Coral and Atolls, p. 89, fig. 241:; p. 93, fig. 27. 



The specimen here considered represents a rough-water facies which has greatly 

 puzzled me. At first I thought it might be an environmental adaptation of A. 

 scherzeriana, but it lacks the mural costulation of that species. The following is 

 Brook's description of A. ocellata: 



"Corallum low, cespitose, 8 to 10 cm. wide and 2 to 4 cm. high. Branches digitiform, 

 obtuse, little divided excepting near the apex, 2 to 4 cm. long, I cm. thick. Axial corallites 

 4 to s mm. broad and 1 to 2 mm. exsert, thick-walled with rounded margin and small 



