CORALS FROM MURRAY, COCOS-KEELING, AND FANNING ISLANDS. I25 



The following is a description of a specimen from Murray Island: 



Corailum with gently convex upper surface. 



Coilines obtuse; along the summit there is a furrow to which the outer ends of the septa 

 extend. Width of intercorallite walls 4.5 to 8 mm. 



Width of series, 13 to 17 mm.; length, 60 to 70 mm.; depth of valley, 5.5 mm. 



Septa ID to I centimeter, usually alternating in size, thickened in the wall. The large 

 septa thick, extend to axes of valleys, upper edges arched or flattish; inner edges slope to 

 bottoms of valleys; smaller septa, thin within valleys, do not reach the axis. Two or three 

 thick not very prominent teeth on outer edges of large septa; two to five teeth on edges 

 within the valleys, the uppermost the more prominent and sometimes hollow. Maximum 

 length of teeth 1.25 mm. Septal faces densely beset with small granulations. 



Columella, flat above, composed of closely twisted trabeculae; diameter about 2 by 3 

 mm. Distance apart in valleys about 7 mm. One or two axial septa connect the columellae 

 of adjacent polypites. 



Exotheca composed of arched thick-walled vesicles. Endothecal dissepiments about 

 1.5 mm. apart. 



Stations at Murray Island. — Southeast reef, 1,600 feet from shore, water 10 

 inches deep; and at 1,625 feet from shore, water 14 inches deep at lowest tides; 

 hard, rocky bottom. 



It has already been stated that Dana's Mussa nobilis is a renaming of Mean- 

 drina sinuosa Quoy and Gaimard. The Murray Island specimens appear undoubt- 

 edly to belong to the same species as the specimens referred to Symphyllia sinuosa 

 by Bedot, but they do not precisely accord with typical specimens. The suite in 

 the U. S. National Museum is small, comprising only three specimens, from the 

 southern Philippines. The principal difference between these and the Murray 

 Island specimens is in size, the valleys in the typical specimens being wider and 

 deeper, the septal dentations larger, and the interserial wall sharper. However, 

 around the edges of one Philippine specimen the differences from Murray Island 

 specimen are shght. Width of valleys as small as ll mm., depth 6 mm. The 

 septal dentations of the former are coarser than those of the latter but of the same 

 pattern and arrangement. Although there are the differences indicated, they are 

 of the kind that may be produced by vegetative causes, and therefore can scarcely 

 be considered of specific value. 



Symphyllia indica is closely related to the S. nobilis, notwithstanding its wider 

 and deeper valleys, and apparently is not beyond the range of specific variation. 

 S. acuta Quelch is also close. However, until large suites of specimens have been 

 carefully studied and compared with one another, attempts to determine specific 

 limits and synonymies would be futile. 



Distribution. — Maldives, Singapore, and Rotuma (Gardiner); Murray Island; 

 Amboina (Bedot); southern Philippines (J. B. Steere); New Mecklenburg (Quoy 

 and Gaimard). Not reported from the Red Sea or east of Rotuma. 



Genus ACANTHASTREA Milne Edwards and Haime. 



1848. Acanthastrea Milne Edwards and Haimc, Acad. Sci., Comptes rend., vol. 27, p. 495. 



Type species: Acanthastrea spinosa Milne Edwards and Haime, which is the 

 same as Astrcea echinata Dana. 



Acanthastrea echinata (Dana) var. 

 Plate 50, figs. 2, 2a, and plate 51, fig. i, Dana's type of Astraa echinata; plate 51, fig. 2, var. from Murray Island. 



1S46. Aslraa echinata Dana, U. S. Expl. Exped., Zooph., p. 229, plate 12, figs, i, la-lb. 



1857. Acanthastma ? echinata Milne Edwards and Haime, Hist. nat. Corall., vol. 2, p. 504. 



1914. Fasia hirsuta Matthai, Trans. Linn. Soc. London, 2d ser., Zool., vol. 17, p. 100, plate 24, figs. 7, 8. 



