l62 PAPERS FROM THE DEPARTMENT OF MARINE BIOLOGY. 



In the present paper one previously named species, A. haimei, is reported from 

 Australia for the first time; another species, A. murrayensis, is described as new, 

 but it was probably included under A. rosaria by Brook. 



Acropora (Eumadrepora) pulchra (Brook). 



Plate 66, figures 3, 3tf, a specimen from Cocos-Keeling Islands. 



1893. Madrepora pulchra Brook, Cat. Genus Madrepora, p. 44, plate 28, fig. A. 



1907. Madrepora Wood Jones, Proc. Zool. Soc. London for 1907, plate 17, fig. 2, b (right-hand figure) 



1910. Madrepora Wood Jones, Coral and Atolls, p. 89, fig. 24, b (right-hand figure). 



Brook based this species on a specimen collected by H. O. Forbes in Keeling 

 Island. Dr. Wood Jones has collected one branch which seems referable to it. The 

 branch is 14.5 cm. long; 9 mm. in diameter at the lower end; axial corallite damaged, 

 about 3.5 mm. in diameter. There are no subdivisions and only one proliferous 

 corallite. Two cycles of septa well developed in the axial corallite. Ccenenchyma 

 of loose texture. The character of the radial corallites are as described by Brook. 



This specimen differs from Brook's description, and also from the Murray 

 Island specimens of var. alveolata, largely in its greater attenuation, without sub- 

 ordinate branching; but this character, as well as the loose texture, may be due to 

 its habitat, in quiet lagoon water. 



Habitat, Cocos-Keeling Islands.— Dr. F. Wood Jones states that the species 

 lives in still water, within the lagoon area. 



Acropora (Eumadrepora) pulchra var. alveolata (Brook). 

 Plate 66, figures 1, 2, specimen from Murray Island. 

 1893. Madrepora pulchra var. alveolata Brook, Cat. Genus Madrepora, p. 45, plate 28, fig. C. 



The following description is based on one larger and four smaller fragments, 

 all perhaps from one colony, collected 1,000 feet from shore, Murray Island: 



Corallum loosely branching; frequently 3 or 4 branches from the same level; angle 

 with main stem 45° or greater. Main stems and branches slender, slowly decreasing in 

 diameter toward the apex. One branch measures 78 mm. long; 9.3 mm. in diameter at 

 base; axial corallite at tip of branch, 3 mm. in diameter. A broken branch on the same 

 specimen is 68 mm. long; diameter at base 10 mm.; at end, 6.5 mm.; decrease in diameter, 

 3.5 mm. in 68 mm., or about 1 mm. to 20 mm. in length. Other specimens show still more 

 gradual tapering. 



Axial corallite, diameter about 3 mm.; protuberant, about 3.5 to 4 mm.; diameter of 

 calicular aperture, about 1 mm. Walls of the corallite about 1 mm. thick; structure reticu- 

 late, porous, but the area of the solid elements exceeds that of the pores; outer surface with 

 longitudinal, plate-like costules, between which are numerous synapticulae, their margins 

 subentire near the calicular aperture, but irregularly dentate near the level of the uppermost 

 radial corallites. Septa, 12 in number, primaries the more prominent, nearly meeting deep 

 down in the calice; secondaries smaller but distinct. 



Radial corallites of two kinds, protuberant and immersed or subimmersed. I he pro- 

 tuberant calices are more prominent near the ends of branches, where they may project as 

 much as 2.25 mm. The outer wall is often somewhat thickened; it may be nearly perpen- 

 dicular or may make an angle of about 45 with the surface of the branch, while the plane 

 of the aperture is either nearly at right angles to the branch, or it may be slightly lower next 

 the branch than on the sides of the corallite, with a slight excavation of the outer margin. 

 The inner wall is distinguishable, sometimes free, but usually not protuberant. The texture 

 of the wall is porous, the outer edge thin and often somewhat ragged; plate-like costules are 

 distinct on the lower, outer surface. The calicular apertures are broadly elliptical, with 

 longer axis in the radial plane, or subcircular; diameter about 1 mm. The directive septa 

 conspicuous; other primaries small, but distinguishable; two secondaries, one on each side 



