(JO Part second. 



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 even 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 con- 

 dition. A specimen will be found enclosed in a small glass at the bot- 

 tom of tank 21. 



MEDUSJE or JELLY-FISH. 



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. 79) and Cotylorhiza 

 (Fig. 80), or with the smaller Pelagia (Fig. 81), Tima (Fig. 82), Olindias 

 (Fig. 84), Carmarina (Fig. 83) 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, 

 generally hollow, gelatinous stalk, also transparent; it is provided at the 

 end with an aperture, the mouth. In some jelly-fish, however, the stalk 

 is short and divided into a number of small lappets, each of which 

 bears a mouth leading into a common cavity, the stomach. From the 

 edge of the umbrella hang down long tentacles, which the animal can 

 at will contract and elongate to a considerable extent. These tentacles 

 are provided with numerous stinging-cells , such as have been described 

 in the case of the Actinias (see p. 56); and, as there, they afford an 

 efficient means of defence for the delicate body. The unpleasant stings 

 experienced occasionally in sea-bathing are generally due to contact with 

 these jelly-fish. Some species, indeed, which attain a size of one to 

 two feet and a weight of 50 to 60 pounds, produce very dangerous 

 stings. 



A few species shine at night with a greenish light; thus Pelagia 

 has received the specific name of noctiluca ("night-lantern" ; not to be 



