152 PAPERS FROM THE DEPARTMENT OF MARINE BIOLOGY. 



Surface foveolate. Calices crowded, apertures distinct; 0.5 to 0.7 mm. in diameter; 

 distance apart 0.5 to 1 mm. A distinct circumscribing wall present, upper edge considerably 

 below the coenenchymal surface. 



Septa, one complete cycle of 6 extends half-way or more than half-way to the columella. 

 Plane of symmetry well marked by an elongate septum or by two opposed elongate septa, 

 the inner ends of which are thickened deep down in the calice and form a columella of solid 

 appearance. Second cycle of septa smaller, usually 4 in number; in places the cycle is complete. 



Coenenchyma, surface minutely spinulose, without papillae or tubercles, composed of 

 a reticulum which shows costal striations around the calices. 



Station, Murray Island. — Southeast reef, line I, Lithothamnion ridge, 1,720- 

 1,775 feet from shore. 



Distribution. — Great Barrier Reef and Northeast Australia. 



This is a small-calicled foveolate species, which, it seems, can only be M. 

 turgescens. I strongly suspect that Bernard's M. libera belongs to the same species. 



Montipora cocosensis, new species. 

 Plate 63, figures 1, la, lb, specimen from Cocos-Keeling Islands. 



The following is the description of this species: 



Corallum forming compressed, irregularly bent, and lobate branches up to 70 mm. or 

 more in height. Diameter of proximal end of a branch 17 by 18.5 mm.; on the same stock, 

 a branch on the distal side of a fork, 15 by 27 mm.; 4 mm. below the end of a lobe, another 

 stock, 6.5 by 10 mm. Ends of lobes with sloping or curved sides, or with longitudinal 

 swellings. Calices on the branch and lobe summits as well as on the sides. 



Calicular margins depressed, walls not always completely developed, where present 

 thickish and compact. Diameter of calices, 1.25 to 1.5 mm., measured from outside of 

 walls. Diameter of depressions in which the calices occur, 1.5 to 2.5 mm. 



There are two complete cycles of septa, which frequently have a distinctly poritid 

 arrangement. The primaries are the more prominent, and fuse by their inner ends to form 

 a more or less compact columella. Usually there may be recognized a solitary directive, 

 with a triplet opposite, the laterals of the triplet fusing to the columellar mass by their 

 inner ends and not notably inclined toward the included directive. The secondaries of the 

 lateral pairs bend toward the respective primaries and fuse to their sides near the columella. 

 This is the scheme of the septal arrangement, but it is not uniformly regular. The septa are 

 composed of trabecular which project horizontally inward, and therefore have the septal 

 structure of Montipora, not that of Porites, in which the septa are composed of ascending 

 trabecular with cross fusions. The larger septa are laminate; no suggestion of pali. 



The ccenenchyma is composed of a wide, axial streaming layer, the threads bending 

 outward and surging upward into a crest, usually sharp, between the calices. Summits 

 with minute radial striations and some small points, but no tubercles. 1 he surface of the 

 reticulum is flaky in appearance. 



One process has grown downward and formed a concavity, arched upward, in which the 

 characters of the lower surface are shown. The calices are from less 0.5 mm. to about 0.75 

 mm. in diameter; from 0.5 to more than 1.5 mm. apart; circumscribing walls as distinct 

 rings, usually slightly protuberant. Septa distinct, small; cyclical development irregular. 

 Ccenenchyma, surface plane; forms an open, rather loose reticulum. 



Habitat, etc., Cocos-Keeling Islands. — Dr. F. Wood Jones states as to these 

 specimens: 



"Common in the inlets and on the lagoon side of barrier flats, at the southern side of the 

 lagoon. Color, while alive, a rather conspicuous yellow; zooids, paler." 



This species belongs in Bernard's section Foveolate Montipora;, and in the 

 subdivision of this section in which the branching forms are placed. He includes 

 the following species, viz, M. gaimardi Bernard, M. indentata Bernard, M. pal- 

 mata {non Dana), M. rigida Verrill, M. limitata (Ellis and Solander). It is no 

 one of these. 



