164 



PAPERS FROM THE DEPARTMENT OF MARINE BIOLOGY. 



Radial coratlites unequal, proliferous and non-proliferous, protuberant and immersed 

 or subimmersed. The non-proliferous protuberant corallites attain their full size near the 

 branch ends, within about 5 mm., where they are spreading at right angles or ascend 

 slightly; length 2.5 to 3 mm.; diameter 2 mm.; with a thicker lower wall, a poorly developed 

 upper wall, and a nariform aperture. Lower down the outer end of the lower wall may 

 curve upward, producing a form like half a canoe. Texture reticulate but rather dense; 

 costules distinct, plate-like. Lower still the corallites decrease in prominence, and are 

 nariform, appressed tubular, or labellate, merging into immersed corallites. Directive 

 septa distinct, other primaries small, secondaries inconspicuous or absent. The protuberant 

 corallites grade into tubular, proliferous corallites 4 mm. long and 2.5 mm. in diameter, 

 which in their turn grade into branchlets. In these the primary septa are well developed 

 and often a few secondaries are distinct. Some small immersed or subimmersed corallites 

 scattered between the prominent ones. 



Ccenenchyma echinulate and costulate, becomes rather dense. 



Station, Murray Island. — Southeast reef, line I, 800 feet from shore; depth, 

 about II inches; bottom, broken coral. 



Distribution. — Red Sea; Indian Ocean; Fiji Islands (Brook and others); Great 



Barrier Reef. 



The growth-form of this specimen is very similar to that represented by von 

 Marenzeller's figure 47 (plate 16). One of the striking features of the species is 

 the prominence of the radial corallites almost to the tips of the branches. This is 

 the first record of the species from the Great Barrier Reef. 



Acropora (Eumadrepora) haimei (Milne Edwards) var. 

 Plate 66, figures 4, 5, specimen from Murray Island. 



The following is a description of specimens of Acropora haimei variety: 



Corallum loosely branching; three branchlets radiate from same level on main stem. 

 Dimensions as follows: 



Measurements of main stem and branches of Acropora haimei var. 



The smallest branch makes an angle of about 60° with the stem; the largest has an 

 initial angle of about 60°, but later points more nearly upward, curving so as to make an 

 angle of 45° to 50°. 



Axial corallites, diameter from 2.75 to 3.5 mm.; aperture 1.25 mm. in diameter; pro- 

 tuberant about i.i; mm.; walls porous, radiately reticulate, i mm. or somewhat more thick; 

 outer surface longitudinally costulate. Costules as narrow plates, with perforations in the 

 interspaces. Septa in two complete cycles; the directives meeting deep down in the 

 calice; the other primaries extend a little more than halfway to the axis; the secondaries 

 well developed, length about one-third that of a radius. 



Radial corallites, both protuberant and immersed. Of the protuberant, one is occa- 

 sionally proliferous; angle with surface of branch about 45°; somewhat taller near the ends 

 of the branches, up to 3 mm.; diameter about 2 mm.; nearly the same from base to aper- 

 ture. Outer wall thicker than inner, with rather prominent plate-like costules, perforate 

 in the furrows, margin not rounded or constricted, except near the base of the stem, where 

 there are some nariform corallites. Inner wall thin and slightly developed, except in 

 rare instances, but appears always to be distinct; the usual height is probably about 

 one-third that of the upper side of the corallite. The corallites are very slightly or not 

 at all laterally compressed. Apertures dimidiate (see Dana, plate 30, fig. 712). The direc- 



