5°6 
CCE LENTERA TES. 
The mushroom-corals (Fungiidce) are another remarkable group of solitary 
forms, taking their name from their resemblance to the head of an expanded mush¬ 
room turned upside down. Turning to the figure of Thecocyathus (on p. 505), and 
imagining the circular wall pulled down all round, and drawing down the septa so 
that they radiate outwards, some idea of a Fungia may 
be obtained. Their skeletons are remarkable objects, which 
no one, at first sight, would in any way connect with a sea- 
anemone. Although the mushroom-corals are considered 
to be individuals, reproducing themselves by means of 
eggs, both budding and division into halves occur excep¬ 
tionally ; in the former case the buds sooner or later 
becoming detached. In some there is an alternation of 
generations, leading to the formation of compound stocks. 
In the illustrated form true mushroom-corals are produced 
at the ends of the branches; at a one has become detached, 
mushroom - coral budding and an( J the others are in different stages, the youngest being 
FORMING A SMALL STOCK , ........ , . . . . . 
(nat. size). nearly cylindrical, like a typical polyp, whereas the older 
ones spread out like a typical Fungia. When a bud has 
fallen off, the stem seems capable of developing another. This is the asexual genera¬ 
tion, reproduction by eggs being the sexual generation. Lastly, certain solitary corals 
have recently been discovered in the deep sea, where, on account of the presence of 
carbonic acid in suffi¬ 
cient quantities to 
make itself felt, there 
is little lime. On this 
account the calcareous 
skeleton is generally 
distinguished by great 
delicacy. A deep-sea 
coral with such a deli¬ 
cate skeleton (Lepto- 
penus), found off the 
east coast of South 
America at a depth of 
over a mile, is shown 
in the illustration. Its 
pedestal is formed of a 
delicate network with 
fine rays or spokes, 
connected together in a 
regular manner by 
transverse supports. 
Plentiful as are the solitary corals, they are surpassed in number by those 
which form compound stocks; that is to say, in which the buds do not fall off' but 
go on budding till coral - islands and barrier - reefs are built up. As it is im¬ 
possible to give here more than a very few illustrations of the many different ways 
deep-sea coral, Leptopenus discus (nat. size). 
