Tank No. 20. 
21 
separate male and female colonies, besides those which bear both sexes; 
sometimes, too, hermaphrodite polypes (individuals with male and female 
reproductive organs) are found. The egg develops within the maternal 
polype into a pear-shaped being, which makes its way out through the 
mouth of the mother-polype and swims about freely for some time; after 
this it fixes itself with one end and becomes transformed into a polype; 
which forms new individuals by budding and thus gives rise to a new colony. 
The Red Coral is a gift of the Mediterranean. Here it grows on 
rocky banks near the coast at a depth of from 40 to 100 fathoms, 
rarely deeper, and is especially exploited on the Ionian Islands and on 
the coasts of Algiers and Tunis; the last named place alone yielding 
about 60,000 pounds a year valued at two million francs. There is also 
a coral bed between Naples and Capri, and from this one the specimens 
in the Aquarium are obtained. The apparatus for coral-fishing consists of 
a cross made of heavy wooden beams, to which are attached pieces of 
old nets, untwisted rope ends and other such material; the whole is 
dragged by means of a strong rope over the bottom of the sea. The 
branching corals are entangled in the nets and ropes, break off and are 
pulled up with them. To use the corals the "bark” with the polypes is 
brushed off and the outermost layer of the skeleton filed away; after¬ 
wards it is ground with emery-powder and oil, and finally polished with 
steel. The beads are turned and pierced on a lathe, the figures are cut 
out with graving-tools. The value of corals varies already greatly before 
they are worked. The thicker roots are often perforated by boring animals 
(worms and sponges) and fetch between 5 and 20 frs. per kilogramme. 
Good ordinary pieces are sold at 40—70 frs. and choice, salmon-coloured 
pieces 400—500 frs. and even more; i. e. 200 to 250 frs. a pound. 
In the Aquarium the Red Coral, inhabiting usually deeper waters, 
does not last long and is therefore generally not seen in a living condition. 
A specimen will be found enclosed in a small glass at the bottom of tank 21. 
MEDUSAE or JELLY-FISH. 
(Tank No. 20.) 
Those who come from northern seas, and remember to have found 
on the sands ugly and offensive masses of jelly, will find it difficult to 
associate these with the large .Rhizostoma (Fig. 18) and Cotylorhiza 
(Fig. 19), or with the smaller Pelagia (Fig. 20), Tima (Fig. 21), Olindias 
(Fig. 22), Carmarina (Fig. 23) etc.; the living Medusae have a very different 
appearance indeed. Their almost complete transparency, the beauty of 
their movements, and often their brilliant colouring make them very 
attractive objects. As they swim, they take the form of a mushroom or 
an open umbrella, the regular opening and closing of the umbrella driving 
them upwards. Round its edge are situated the sense-organs, probably 
of seeing and hearing. 
From the centre of the under surface of the umbrella hangs a long, 
hollowq gelatinous stalk, also transparent; it is provided at the end with 
an aperture, the mouth. This is best seen in Carmarina. In some 
