204 PAPERS FROM THE DEPARTMENT OF MARINE BIOLOGY. 



Septa thick, sides densely and coarsely granulate; interseptal loculi correspondingly 

 narrow. A synapticular ring just within the wall, with a ring of rather ragged, tangentially 

 compressed denticles above it. The wall, the outer synapticular ring, and the outer denticles 

 by thickening may form a reticulum of flaky appearance. Just within this ring of denticles 

 is a second ring which is between the outer one and the pali. The palar synapticular ling 

 is weakly developed, notwithstaning the thick septa. 



There are usually 6 stout, tall, densely granulate pali; one before each of the 4 lateral 

 pairs, and one on each of the directives, but the one on the solitary directive frequently 

 corresponds to the intermediate denticles of the other septa. Although the laterals of the 

 triplet usually fuse by their inner ends to the included directive, the intermediate denticles 

 may be so prominent on each member of the group as to simulate pali while the morpho- 

 logic palus is small and pressed against the columellar tubercle. In some calices pali appear 

 before the laterals of the triplet, the one on the directive apparently being suppressed. One 

 of the striking characters is the great development of the intermediate denticles and the 

 tendency for them to become confused with the pali. 



Columella a conspicuous, granulated style, slightly less stout than the pali and usually 

 not so tall, but often equaling or nearly equaling them in height; joined to the septa by a 

 variable number of radii; five is a frequent number. 



Stations at Murray Island. — Southeast reef, line I, as follows: 



400 feet from shore; depth of water, 4.5 to 5 inches. 

 600 feet from shore; depth of water, 15 inches; bottom mud and sand. 

 650 feet from shore; depth of water, 10 inches; bottom sandy. 

 800 feet from shore; depth of water, 11 inches; bottom hard, rocky. 

 1,200 feet from shore; depth of water, 9 inches; bottom rocky. 



The foregoing description is based on a broken colony from 400 feet from shore, 

 which in the character of its branches differs considerably from one specimen from 

 600 feet from shore and those farther out on the reef flat. The branches are more 

 crooked, more interfused, and the deptli of the living tissue is less. These charac- 

 ters are such as would result from an unfavorable environment. The following are 

 notes on the different specimens. 



600 feet from shore, 3 specimens: (a) a good colony; branches interfusing except near the 

 tips, free as much as 17 mm.; depth of living tissue, as much as 67 mm.; in places an elevated 

 mural thread may be traced between the calices; surface low down on the branches appears 

 velvety, because of the great development of mural and septal denticles, in these areas the 

 reticulum is greatly developed and flaky; calicular characters similar in scheme to those given 

 in the detailed description, (b) 3 fragments, 2 from one colony; branches not interfused, 

 otherwise no important difference from (a). 



650 feet from shore, 1 specimen; not notably different from (b) of the preceding note. 



800 feet from shore, 2 good specimens: both have the branches and branchlets free. 

 (a) Closely similar to specimen on which the detailed description is based, except that the 

 branches are not so crooked and do not interfuse, (b) Similar to (a), except that the branch 

 terminals may be compressed and wide (plate 91, figs. 1, id), width up to 24 mm. and about 

 5 mm. thick. 



1,200 feet from shore, 1 good colony (plate 91, figs. 2, 2a), branches free, rather diver- 

 gent; most of the surface velvety, with the appearance of bloom on it, but two branchlets 

 are similar to those of the other specimens. 



The variation consists mostly in the form of the colony, whether the branches 

 are or are not interfused, and whether crooked or rather straight; and in the degree 

 of the development of the flaky reticulum and its associated denticles. It is on 

 the latter that the velvety appearance of the surface of the older parts of the coral- 

 lum depends. The columellar style may be only a small point. Therefore, the 

 detailed description needs only slight modification to comprehend the specific 

 characters, which are the growth-form, and the mural and calicular characters. 



This coral is the one designated by Bernard Porites Great Barrier Reef (42)12, 

 and is probably also his Porites Great Barrier Reef (42)42. 



