174 MADREPORARIA. 
5 mm. long, wall very thick and dense, margin rounded, aperture very small. Radial 
corallites unequal, very spreading, mostly at right angles or nearly so; the longer ones 
tubular, 3 to 5 mm. long and 3 mm. in diameter, wall thick, margin rounded, aperture 
0°5 mm. or a little over. Between these, numerous smaller, short, cylindrical or verruciform 
ones occur, but none are completely immersed. In the forms which extend more or less 
obliquely, the underside has fewer or more distant corallites, often without aperture. 
Corallum very dense; surface covered with crowded elongate echinulations ; wall finely 
echinulate, not striate. In the axial corallites the star consists of 12 septa, the primaries 
subequal and the second cycle narrow; in some of the radial corallites a second cycle does 
not occur. 
A. Var. fortis, Klunzinger. 
Corallum 40 em. high and wide. Branches 2 cm. thick, bearing numerous spreading 
branchlets about 2°5 em. long and 1°5 em. thick. Axial corallites 5 to 6 mm. thick ; radial 
corallites 4 to 5 mm. long and 4 mm. thick. Many of the most prominent corallites are 
6 mm. long and 4 to 5 mm. broad at the base, wall tapering; some bear a few bud-corallites 
near the base. 
B. Var. obtusata, Klunzinger. 
Corallum laxly arborescent, branches blunt at the apex. Axial corallites 5 mm. 
diameter, little exsert. Radial corallites rather short and stunted, cylindrical, not conical, 
3 mm. broad and 3 to 4 mm. long, forming with the stem a wide acute angle. 
C. Var. variolosa, Klunzinger. 
Corallum laxly arborescent, with ascending digitiform branches. Stem 2 em, thick, 
branches 3 to 10 em. long, 1°5 mm. thick at the base, 1] cm. at the apex. Axial corallites 
4 to 5 mm. broad ; the majority of the radial corallites are 3 to 5 mm. broad and 3 to 4mm. 
long, but a few small verruciform ones are scattered between. 
D. Var. depressa. 
Corallum prostrate (?), with few branchlets and corallites on the under surface. Branch- 
lets on the upper surface’ arched upwards, 3 to 6 cm. long, 1 cm. diameter, gradually 
tapering, their apices about 2 cm. apart. Axial corallites 3°5 to 4 mm. diameter, 2 to 3 mm, 
exsert. Radial corallites spreading tubular, 3 mm. diameter, mostly elongate (3°5 to 6 mm.) ; 
some of the longer ones bear a few bud-corallites. The lower part of the branches bears 
subimmersed corallites and others are completely immersed. A star of 12 septa is distinct 
in nearly all the corallites. 
