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THE SEA-FAN. 
In the accompanying illustration is seen a figure of that remarkable coral which is 
popularly called BRAIN-sToNE, or BRAIN-cORAL, because the convolutions into which the 
corallum is moulded much resemble those of 
the human brain. 
The animals of this genus are always 
united together in long waved series, each 
having a distinct movth and series of very 
short tentacles. The cells are very shallow, 
2 a Eee and the valleys formed by their union are 
pore me Se 4 separated from each other by distinct ridges. 
; a i. oe od ey The shape of this coral alters greatly with 
eK es « ee = age, somewhat resembling the top-shells when 
young, but becoming rounded above when 
adult. The Brain-coral is found in several 
of the hot seas. 
Among the Asteriadee, as these creatures are called, in consequence of the star-like 
appearance of the polype or animal, the ORGAN-PIPE-CORAL is perhaps the most striking. It 
forms, as far as is yet known, the only example of the group to which it belongs, and which is 
called Tubuliporina, on account of the multiplied series of regular tubes from which it is 
formed. As will be seen by reference to our engraving, in this beautiful coral the tubes are 
arranged like the pipes of a church-organ, or the storied rows of basaltic columns of the 
Giant Causeway. 
The color, too, is very pleasing, being a delicate pink, so that even the empty and lifeless 
corallum forms a really beautiful object. When living, however, it may fairly lay claim to 
the title of magnificent, for each tube is clothed, formed, and vivified by a light green polype, 
whose color contrasts beautifully with that of the structure which is raised by that soft and 
feeble body. 
Two other species of true coral, such as are used so largely in the manufacture of orna- 
ments, are termed Cordllium fecundum and Cordllium nobile. 
These beautiful zoophytes seem to be found only in the Mediterranean, where regular 
fisheries are established and the corals 
dragged from their recesses. The appli- 
ances, however, are very rude; and it 
is likely that more elaborate machinery 
would reap a rich harvest by permitting 
some selection to be made and by ena- 
bling the fishers to regulate the dimen- 
sions of the groups of coral branches. 
Although the stony centre is so thick 
and solid, the substance of the animal 
is quite delicate and membranous, en- 
veloping the corallum like wetted gold- 
beater’s skin. 
A fan-like object is popularly called 
from its shape, the Sra-Fan (Gorgonia 
Jlabellum), and well deserves that title. 
In this genus the branching arms are 
united by a number of transparent ORGAN-PIPE CORAL. Tubipara springa. (Natural size.) 
pieces, which are, in fact, developments 
of the branches, are covered in a similar manner by the investing membrane, and bear the 
living polypes on their surface. The whole structure easily dries, and may be found in most 
curiosity shops, or in the dwelling-houses of mariners, who have brought home these remark- 
able objects as presents to their wives. 
The Gorgénias, Sea-fans, Sea-feathers, Sea-whips, ete., belong to the Order Halcyonoida 

BRAIN-CORAL.—Astrea pallida. (One-half natural size.) 

