CORALS FROM MURRAY, COCOS-KEELING, AND FANNING ISLANDS. 187 



There are six prominent septa, considered primary septa, which are thicker than the other 

 septa and extend to the columella. They slope steeply in their upper part, widen below, and 

 bear conspicuous paliform lobes, which do not reach the level of the top of the wall, but stand 

 above and surround a narrow columellar fossa. The secondary septa are smaller than the 

 primaries but are well developed; they fuse to the sides of the primaries near the columella. 

 The tertiaries are small; sometimes they fuse to the sides of a primary,!, e., one of the largest 

 septa, but usually are represented by vertical rows of spines. Septal faces, especially the 

 paliform lobes, coarsely granulate. 



Columella present, variable in development, composed of a few rather coarse inter- 

 fusing trabeculae connected with the septa. It averages in diameter about or somewhat 

 less than one-third that of a calice. 



Specimen on which the preceding description is based obtained from station at Murray 

 Island, southeast reef, line I, about 600 feet from shore; water about 15 inches deep; bottom 

 sandy. 



(2) Specimen from station 500 to 5 50 feet from shore, water about 15 inches deep, sandy 

 bottom: Growth-form pulvinate; greater diameter, 67.5 mm.; lesser, 47.5 mm.; height 

 39 mm. Average diameter of fully developed calices 2.5 mm.; fossae, deep. Walls thin, 

 simple, or walls of adjacent calice with cells between costal ends of septa. Primary septa 

 well developed, fusing to columellar tangle, but thinner than in the specimen of the preceding 

 description; paliform thickenings and lobes only indicated, not greatly developed. Although 

 the growth-form and the septal plan in this and the preceding specimen are the same, the 

 secondary and tertiary septa of No. 2 average less prominent, its calices are smaller, and its 

 structural elements are thinner and otherwise less developed. 



(3) Two specimens, southeast reef, line I, 600 feet from shore; water about 7 inches 

 deep at low tide: General characters similar to No. 2, but show complete intergradation 

 with No. 1. In one of the two the septa are thin. The paliform lobes are thin and form 

 irregular plates on one part of the specimen, while on another part, near the edge, they 

 are thick and prominent. 



(4) Specimen from 600 to 650 feet from shore; water 8 inches deep; sandy or muddy 

 bottom: A small colony. Calices 2.5 to 3 mm. in diameter. Primary septa thick; pali 

 thick and prominent. Secondary septa well developed; tertiaries variable in development. 



(5) Specimen (see plate 84, fig. 1) from southeast reef, line I, 800 feet from shore; 

 water 11 inches deep; bottom hard, rocky: Calices about 3 mm. in diameter; pali usually, 

 but not uniformly, thick and prominent. 



(6) Three specimens from southeast reef, line I, 1,000 feet from shore, water 17 inches 

 deep; bottom rocky: Smaller and larger calicled variations occur at the same station; 

 higher cycles of septa more irregular in the smaller-calicled specimen. In one small specimen 

 (see plate 84, fig. 2) nearly all of the bottom of the polypite cavity is filled by the compacted 

 and cemented inner ends of the septa, the prominent pali, and the columella, but the growth- 

 form and scheme of arrangement of the skeletal structures is the same as in the other 

 specimens. 



(7) Specimen from southeast reef, line I, 1,200 feet from shore; water 9 inches deep; 

 bottom rocky: Small specimen; calices 2.5 to 3.5 mm. in diameter; pali thick and prom- 

 inent, usually interfused with the septal ends and columella and the filling occupies most 

 of the bottom of the calice. 



(8) Specimen from southeast reef, line I, 1,400 feet from shore; water 14 inches deep; 

 bottom hard, rocky: Calices 2.5 to 3 mm. in diameter; pali usually strongly developed. 



(9) Specimen from southeast reef, line I, 1,600 feet from shore; water 10 inches deep; 

 bottom hard. Similar to No. 8. 



(10) Two specimens, station on reef not indicated. One of these has calices 2.5 to 

 3 mm. in diameter; septa average thin and fragile; pali poorly developed. The other 

 specimen shows great variation between its two ends. On one end, calices 3 to 3.5 mm. 

 in diameter; septa thin and fragile; pali indistinct or poorly developed; columella lax, 

 composed of loosely fused irregular trabeculae. On the other end, calices slightly smaller; 

 septa thicker; pali prominent; septal ends, pali, and columella fused and compacted so 

 as to fill most of the bottom of the calice. 



It seems scarcely necessary to summarize into a general description the data 

 given in the preceding descriptions, as that of specimen No. 1 applies to all in its 

 essentials. The principal variation is in the amount of thickening of the skeletal 

 elements and in the degree of development and thickening of the pali. 



