CORALS FROM MURRAY, COCOS-KEELING, AND FANNING ISLANDS. 107 



in the thecal ring. Upper edges exsert up to 1.5 mm.; dentations fairly regular. Inner 

 margins sloping or perpendicular, with coarser dentations, the longer near the columella. 

 Faces with small conical granulations. 



Erect paliform teeth on the end of the principal septa surround the columella, which 

 is trabecular, and about one-quarter the diameter of the calice. 



Exothecal vesicles in a single row between corallites, walls thick, about i mm. apart; 

 dissepiments thick, about i mm. apart. 



Reproduction by unequal fission. 



From station at Murray Island, 1,600 feet from shore, line I, southeast reef. 



Facies 2 (plate 38, fig. 3). 



Facies 2 differs from Facies i in the following particulars: 



(i) The calicular margins are more elevated, up to 3 mm.; the calices are more distant, 

 up to 4 mm.; and the intercorallite depressions are correspondingly more distinct. (2) The 

 principal costie are not so tall, and the homologue of the rudimentary costae of Facies i are 

 well developed, but there are no distinct septa corresponding to those costae. 



Facies i and 2 are found on the same corallum from 1,600 feet from shore. 



From station at Murray Island, southeast reef, line I, 1,600 feet from shore, and Litho- 

 thamnion ridge, 1,775 feet from shore. 



Facies 3 (plate 38, fig. 4; also plate 16, fig. 26, of Dr. Mayer's article.) 



Facies 3 differs from Facies 2 by having (i) 7 or 8 septa thicker than the others; 

 (2) more irregular, rougher, and more spinulose septal and costal dentations. Some of 

 the calices of this specimen, except that they are somewhat deeper, up to 4 mm., almost 

 duplicate those of Verrill's type of Astraa cellulosa; other calices closely resemble those 

 of Dana's original specimen oi Astraa versipora (non Lamarck). 



From station at Murray Island, line I, southeast reef, 1,660 feet from shore, water 

 14 inches deep at low tide; hard, rocky bottom. 



Facies 4 (plate 38, fig. 5; also plate 16, fig. 29, of Dr. Mayer's article). 



This is similar to Facies 2, except that in some calices septa of higher cycles may fuse 

 by their inner ends to the sides of septa of a lower cycle. The fusion is usually in pairs, 

 rarely in triplets. 



From station at Murray Island, line I, southeast reef, 1,630 feet from shore; water 

 16 inches deep at low tide; hard bottom. 



Facies 5 (plate 38, fig. 6). 



This is similar to Facies 2, except that the calices are more crowded, usually about 

 1.5 mm. apart. 



From station at Murray Island, southeast reef, line I, Lithothamnion ridge, 1,775 ^^^^ 

 from shore. 



Facies 6 (plate 38, fig. 7; also plate 16, figs. 27, 30, of Dr. Mayer's article.) 



Facies 6 presents peculiarities so striking that it will be described in detail. 



Corallum pulvinate in form, up to 13.5 cm. in diameter, 6.5 cm. thick. 



Calices subcircular, oval, or subpolygonal with rounded angles. Lesser diameter 

 from 6.5 to 9 rnm.; greater up to 12 mm.; 8 by 12 mm. the size of a fully developed calice 

 previous to division. Margins not elevated. Depth up to 5 mm. Thickness of inter- 

 corallite walls, I to 1.5 mm. where distant from corallum edge; up to 2 mm. near the edge. 



The costae are only the outer ends of the septa, usually not continuous between adjacent 

 calices, the ends of the septa outside the septal arch falling steeply, almost perpendicularly, 

 producing the appearance of a furrow between adjacent corallites. Exsert up to 1.5 mm., 

 frequently with intermediate, low costae. 



Septa in a mature calice, 12 by 8 mm. in diameter, 14 reach the columella, 8 almost 

 reach it; about 23 smaller, mostly rudimentary septa; in a small, subcircular calice 10 

 septa extend to the columella. The outer ends thickened in the thecal ring; the inner part of 

 the larger septa strong, rather stout. Upper edges (costal ends) exsert up to 1.5 mm., 

 arch narrow with steep sides, dentations rough, secondarily spinulose, producing a frosted 



