CORALS FROM MURRAY, COCOS-KEELING, AND FANNING ISLANDS. 163 



of the outer directive usually visible; other secondaries obscure or absent. Distance 

 between the walls of adjacent protuberant corallites usually about i mm. Toward the 

 base of branches and on the lower part of main stem, all corallites may become immersed 

 by the outward growth of the coenenchymal tissue; the calicular apertures may become 

 smaller, 0.75 mm. in diameter, and more distant. The immersed and subimmersed coral- 

 lites need no special description. 



The coenenchymal surface near the tips of branches is loosely reticular, porous, somewhat 

 flaky, and with irregular granulations projecting above the reticulum. On the old portions 

 of the corallum the reticulum is coarser, but it is still porous, and granulations occur in 

 wavy rows. 



Stations, Murray Island. — Southeast reef, line I: 



600 feet from shore; water 4.5 to 5 inches deep; bottom sandy; 4 fragments, terminals of branchiets. 

 1,000 feet from shore; water 14 to 17 inches deep; bottom rocky; specimens described. 

 1,400 feet from shore; water 14 to 15 inches deep; bottom rocky, broken coral; 2 broken branches. 

 1,600 feet from shore; water 10 to 16 inches deep; bottom hard, rocky; i branch. 



Brook's description of this variety is satisfactory, but as additional descrip- 

 tions of forms not generally known are desirable, I am publishing that of the Murray 

 Island specimens. One of the principal variations is in the amount of crowding and 

 in the size of the radial corallites. A specimen 1,400 feet from shore has corallites 

 slightly less than i mm. apart and on the lower portion of the branch the diameter 

 is often only 0.5 mm. A specimen 1,600 feet from shore has, on the lower part of 

 the stem, radial calices up to 1.5 mm. apart; margins slightly elevated, somewhat 

 tumid around the base; two cycles of septa, the secondaries small or rudimentary; 

 and an irregularly shaped, slightly prominent, plug-like columella. 



Distribution. — Rocky, Thursday, and Palm Islands, Great Barrier Reef; Torres 

 Strait. 



Acropora (Eumadrepora) haimei (Milne Edwards). 



Plate 70, figures 3, 3a, 3^, specimen from Murray Island. 



i860. Madrepora haimei Milne Edwards, Hist. nat. Corall., vol. 3, p. 151. 



1893. Madrepora haimei Brook, Cat. Genus Madrepora, p. 77. 



1907. Acropora haimei von Marenzeller, Denksch. k. k. Akad. Wiss. Wien, vol. 80, p. ;i, plate 16, figs. 45-48. 



A description of a specimen of this species from Murray Island follows: 



Corallum cespitose, rising from an incrusting base. Height about 10 cm.; greatest 

 spread of branches nearly 16 cm. Length of branches between 60 and 65 mm.; diameter 

 at base 9 to 12 mm.; the main branches subdivide 3 or 4 times between the base and 

 summit. Sets of branches from 12 to 30 mm. apart. Branchiets up to nearly 40 mm. 

 long, basal diameter 7 mm. The following are measurements of branchiets: 



Axial corallites, dimensions as given in table. Walls, thickness somewhat less than 

 one-third the corallite diameter; texture relatively dense; outer surface with distinct, 

 plate-like costules, with synapticulse in the intercostular spaces. Septa in two well-developed 

 cycles; the primaries may meet deep down; secondaries smaller but distinct. 



