98 MADREPORARIA. 
The following is a description of the specimen in the Paris Museum, which is regarded as 
Lamarck’s type :— 
Corallum openly vasiform and pedicellate, 29 cm. diameter, and 11 em. high. The 
branches of which the vase is composed have a length up to 15 cm., and are 1 cm. diameter 
near the base; the branches are crowded, with long narrow spaces between, but fusions are 
numerous to near the margin of the vase. There are numerous-immersed and subimmersed 
corallites on the under surface, and also a large number of wart-like buds, which consist of a 
central tubercle about 3°5 mm. long and 3 mm. diameter, with a few subimmersed corallites 
around. These bud-branches are mostly at right angles to the under surface, but a few 
which are lateral become branched, pressed into: the general plane, and may attain a length 
of 15 em. The superior surface of the main branches is clothed with immersed or short 
labellate corallites. Innumerable short branchlets arise from this surface, having a maximum 
length of 2 cm., and 6 or 7 mm. diameter at the base; they are rapidly tapering, arched so 
as to reach the same level, mostly proliferous, but a few are simple. Axial corallites 1°5 
mm. long and broad, wall firm. Radial corallites half-tubular or labellate at an angle of 
about 45°, a little over 2 mm. long and over 1 mm. thick, very fragile, becoming rapidly 
shorter below the proliferous apices. Septa of the axial corallites moderately developed, a 
second cycle sometimes recognizable; in the radial labellate and immersed corallites the 
directives are very narrow and the others rudimentary. Corallum fragile and very porous 
in section ; surface strongly echinulate and reticulate, but firmer on the main branches ; wall 
strongly ribbed and echinulate, reticulate between. 
This species is extremely variable, both in habit and in the character of the corallites, 
and many specimens which are referable to it differ in a marked degree from the type 
specimen. The axial corallites are cylindrical, usually 2 or occasionally 3 mm. broad and 2 
to 3 mm. long, with the wall a little thickened; the size varies considerably in different 
specimens. Radial corallites half-tubular, dimidiate or spathulate, 1 to 2 mm. broad and 
2 to 3 mm. long, more spreading and crowded near the apex ; immersed at the base of the 
branchlets and on the stouter parts. The under surface in the subcomplanate forms always 
bears numerous short twigs and elongate tubular corallites up to 4 or 5 mm. in length. The 
form of the colony is either :— 
a. Vasiform or subvasiform. (Var. vasiformis.) 
6. Hemispherical or bushy, with slender elongate middle branches and short, much divided 
marginal ones. (Var. hemispherica, Ehrb.) 
Broad corymbose, convex on the upper surface, with the branchlets and corallites as in 
form d; compare Klunzinger’s pl. ix. fig. 16. (War. corymbiformis.) 
d. Cespito-tabulate, with the main branches extending horizontally, and the branchlets 
short and stout. (Var. cespito-tabulata, K1z.) 
Incrusting, without or with much depressed branchlets, as in M. seriata, var. depressa. 
(Var. depressa, K1z.) 
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Klunzinger observes that some specimens of the cespito-tabulate form are similar to 
M. cytherea, Dana, but may usually be distinguished by the less pointed corallites, the less 
developed branches, and the less naked under surface. In other cases, however, it is 
extremely difficult to separate the two forms, and ultimately it may be necessary to regard 
both as varieties of one species. 
