174 PAPERS FROM THE DEPARTMENT OF MARINE BIOLOGY. 



of branches about 9 cm.; basal diameter of branches up to 14 mm. or somewhat more. 

 Branches on lower and outer edge of colony shorter and thinner, 3.5 cm. long and 9 mm. 

 in diameter at the base; other branches still smaller. The main branches often subdivide 

 into from 3 to 4 branches near the base; these branches again subdivide into 2 to 4 branches 

 1.5 to 2 cm. higher up, and smaller lateral branchlets originate still higher. Such branchlets 

 range in size from proliferous corallite up to 4 cm. long, with a basal diameter of 8 mm. 

 The branchlets are more numerous on the outside of the outer branches than on those 

 situated more interiorly. Very little or no anastomosis of branches or branchlets. Distance 

 between terminals 1.5 to 2 cm. 



Axial corallites 3 to 3.5 mm. in diameter; exsert, 1.5 mm.; calicular aperture, 1.25 mm. 

 in diameter; walls, 1 mm. thick, texture lax, porous, reticulate, costulate, with synapticulae 

 between the costules; septa in 2 distinct cycles, the primaries nearly meeting deep down 

 in the calices, the secondaries about one-third the length of the calicular radius. 



Radial corallites immersed on the basal expansion and on the lower portion of the 

 branches; higher up there are some proliferous corallites which merge into branchlets. The 

 usual corallites are crowded, spreading, scale-like, only the lower wall developed, rise in 

 close ascending spirals, the lower walls of the next higher spiral rising from the level of the 

 upper margin of the corallites of the next lower spiral, without any immersed corallites 

 between them. Diameter ranges from 2 to 2.75 mm.; length of lip 2 to 2.75 mm. The 

 lower surface of the wall is perpendicular to the axis of the branchlet, while the margin 

 of the aperture may slope slightly downward; farther down on the branch the lower wall 

 ascends and the plane of the aperture is at right angles to the branch axis. Viewed 

 in plan, the outer margin of the wall is rounded, but frequently it is more or less trun- 

 cate, with rounding at the ends of the truncation. Viewed in profile, the outer edge is 

 usually thin, delicate, and friable, but within there may be appreciable thickening. Lower 

 down on the branches the wall may have a rounded edge. The texture is reticular and 

 on the outside there are delicately granulate costules. Apertural outline circular. Two 

 cycles of septa can usually be distinguished, but only the directives are fairly conspicuous, 

 the outer the more prominent, the others small or rudimentary. In the immersed 

 corallites the septa are more conspicuous. 



The ccenenchyma becomes fairly compact; originally it is granulate and flaky. 



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



1,020 feet from shote; water 16 inches deep at lowest tide; hard, rocky bottom, in a protected place free 

 from current (the specimen on which the foregoing description is based, plate 72, figs. 1, 2, 2a, 3). 



1,400 feet from shore; depth, 14 inches; bottom hard, rocky. (A colony nearly the size of the one de- 

 scribed, some anastomosis of branches.) 



1,600 feet from shore; depth, 10 inches; bottom hard, rocky. (One small colony.) 



It is my belief that A. squamosa (Brook) is the quiet-water facies of the same 

 species of which A. sarmentosa (Brook) is the rough-water facies. Additional re- 

 marks will be made under the latter. 



Distribution. — Great Barrier Reef; Australia. 



Acropora (Lepidocyathus) sarmentosa (Brook). 

 Plate 72, figures 4, 4a; plate 73, figure 1, specimen from Murray Island. 

 1893. Acropora sarmentosa Brook, Cat. Genus Madrepora, p. 127, plate 22. 



I am attaching this name to two fragments collected by Dr. Mayer. At first 

 I labeled one of them A. squamosa and the other A. sarmentosa, but they are prob- 

 ably parts of the same colony. I have already stated it is my belief that the latter 

 is the rough-water facies and the former the quiet-water facies of the same species. 



Station, Murray Island. — Southeast reef, line I, 1,600 feet from shore; water 

 10 inches deep at low spring tides. 



Acropora (Lepidocyathus) hebes (Dana). 



Plate 73, figures 2, 2a, Dana's type of Madrepora hebes; plate 74, figures 1, 2, 2a, lb, specimens from Murray- 

 Island. Also plate 13, figure 6, of Dr. Mayer's article. 



1846. Madrepora hebes Dana, U. S. Expl. Exped., Zooph., p. 468, plate 35, fig. 5. 

 1893. Madrepora hebes Brook, Cat. Genus Madrepora, p. 128. 



