﻿120 MADKEPORARIA. 



97. Montipora stellata. 



Description. — Gorallum not closely encrusting, free edges, with weU developed epitheca 

 to within 1 cm. of edge ; about 1 cm. thick at 6 cm. from edge. Edge from 3 to 4 mm. 

 thick. Surface very uneven. 



Calicles elegantly star-shaped, from 0* 50 to 0'75 mm. in diameter, crowded, without any 

 definite margin. Six weU developed primaries extending beyond the half radius circle : one 

 of them is specially pronounced, frequently laminate, and reaches nearly to the centre of the 

 calyx : small secondaries irregularly developed. On the under surface the calicles are 

 minute, star-like and numerous, sui-rounded by thick solid rings deeply cut in to form the 

 interseptal loculi. 



Coenenchyma shows a conspicuous layer of streaming laminate reticulum 3 to 4 mm. 

 tliick ; this forms the growing edge. This layer bends up and only gradually changes into the 

 trabecular layer. The trabeculoe are stout and closely packed together, the junctions being 

 thin and inconspicuous. The tips of the trabecule rise above the surface to form dense 

 crowds of tubercles, irregular in size and distribution, small groups rising taller than the rest, 

 and here and there forming tall rings round calicles. They average ■ 5 mm. thick and 1 mm. 

 high, and are bushy, round-topped columns, their fine branchlets being generally arranged in 

 longitudinal series, making the tubercles look striated when seen sideways under the lens.. 

 On the eminences the tubercles may coalesce to form short ridges, and round the growing 

 edge there is a ridge formation due to the streaming layer and prior to the formation of 

 tubercles. 



Under this heading I have classed two fragments of tuberculate corals which agree in 

 most points, but differ chiefly in the size of the tubercles. In most other respects they 

 resemble one another sufficiently to justify their provisional juxtaposition. 



The running together of the tubercles to form gyrating ridges, especially on eminences, 

 is more pronounced on a than on h, but, owing to the fact that this phenomenon is a very 

 common one and may be due to the accidents of growth, too much stress cannot be laid upon 

 it. The ridges are not radially arranged round the edges as in M. effusa, but twist about 

 irregularly. The patches, however, in which this ridging takes place are very limited, while 

 over the greater part of the surface the tubercles are simple and free. While here and there 

 a ring of tubercles rises round a calicle higher than the rest, there is no special marking of 

 the positions of the calicles by the heights of the tubercles. They rise close roimd the 

 calicle aperture. 



a. Eocky Island, Great Barrier Eeef. CoU. Saville-Kent. (Type.) 



I. Cleveland Bay, „ „ „ „ 



