292 TABULATE CORALS. 



many detached spiniform processes placed at the angles of 

 junction of the larger tubes. Type of the group, Dekayia 

 aspera, E. and H. 



III. CONSTELLARIA, Dana. Corallites of two kinds, the 

 larger ones circular or oval, with well-developed walls, which 

 become somewhat thickened as the calices are approached, the 

 tabulse being few in number and developed chiefly in the 

 outer portions of the corallum. Small corallites developed at 

 the angles of junction of the larger tubes, and more especi- 

 ally in the depressed centres of closely-disposed stellate areas, 

 which project above the general surface as conspicuous star- 

 shaped elevations. Walls of the small corallites imperfectly 

 developed, their shape being angular, or subangular, and their 

 tabulae being numerous and sometimes subvesicular. Type of 

 the group, Constellaria antheloidea, Hall. 



IV. FISTULIPORA, M'Coy (= CALLOPORA, Hall). Corallites 

 of two kinds, the larger ones circular or oval, with few and 

 remote tabulae, but with well-developed walls, which are not 

 thickened towards the mouths. Small corallites completely 

 isolating the larger tubes, round which they are developed in 

 one or more rows, with numerous tabulae, which sometimes 

 become vesicular by imperfection of the walls of neighbouring 

 corallites. The shape of the smaller tubes is markedly angular 

 (sometimes round ?) ; and though they may be specially de- 

 veloped in star-like areas, these areas never project as stellate 

 elevations above the general surface. Type of the group, 

 Fistulipora minor ; M'Coy. 



V. DIPLOTRYPA, Nich. Corallites of two kinds, the larger 

 ones thin - walled throughout, conspicuously polygonal, with 

 comparatively few and remote tabulae, which occasionally are 

 developed in a peculiar bilateral manner, so that the two halves 

 of the tube are provided with tabulae of a different kind and 

 form. The large corallites are usually or always aggregated 

 at special points into conspicuous clusters (" monticules "), but 

 they are at the same time scattered indiscriminately through 

 the entire colony, and except where forming the groups just 



