I lo Part second. 



It is a great rarity for aquatic animals to produce sounds. 

 If some crustaceans and fish can make noises, these are so rare 

 and can be heard only at such short distances that one can almost 

 neglect them. Under the water no sound-waves can arise and 

 even the howling of the tempest and the clash of thunder do not 

 penetrate into this realm of everlasting silence. Now, where no 

 sound-waves can be produced, no organs can develop to make 

 the waters vibrate with sound. The land animals, and those, too, 

 which live in the water but breathe air, can hear, but the aquatic 

 animals are deaf. They can only perceive those waves of the 

 medium which the land animals recognize as sounds, as a trembling 

 or shaking. Courtships, which the land animals so often accom- 

 pany with music, battles between attacker and victim which 

 make the air tremble with the roaring of anger and the shrieks 

 of pain, these are no less eager, no less fierce beneath the water: 

 but here ardour, hunger and the agony of death are silent, and 

 even were they not so, there would be no ear to hear them. The 

 miracle of St. Antony and the fishes is more marvellous than it 

 is usually considered to be. 



A near ally of Trigla is the Flying-gurnard, Dactylopterus 

 (fig. yj), which, however, in spite of its name does not use its 

 large pectoral fins for flying through the air. The Fljang Gurnards 

 live in shoals at the bottom of the sea. Their flesh is tough and 

 tasteless. They grunt like Trigla when caught. They are only 

 occasionally seen in the Aquarium. 



Like the gurnards the Red Mullet, Mullus (fig. 74), lives in 

 flocks on the muddy beds of the sea, feeling about for food with 

 the two long barbules of its lower jaw. In the Aquarium the play 

 of these tactile organs can be well studied. Sometimes they are 

 moved about slowly, and with great deliberation, in the mud, 

 sometimes they vibrate rapidly or are laid back into a furrow of 

 the lower jaw. The Roman gourmands prized this fish very 

 greatly and, when it was the fashion, they paid incredible sums 

 for large specimens. These fish were brought to the guests in 

 glass bowls living, and, so as to enjoy the wonderful play of colours 

 which they show, were allowed to die slowly in the hands of the 

 women. Nowadays the Mullet, under the name of Triglia in all 

 Italian markets, is a much sought-after but not very expensive fish. 

 Young Mullets, which live near the surface of the open sea change 

 the colour of their skin to correspond with that of the water as 

 the migrate in towards the coast where they live when adult. In 

 youth they are blue, but later become yellowish-green. They 

 compose the greater part of the masses of small fish which are 

 eaten in Naples as "Fragaglia". 



The Eels, too, are inhabitants of the rocky beds. The Conger 

 Eel, Conger (fig. 58), and the Roman Eel, Muraena (fig, 66), will 

 be found in tank No. 11 where they generally hide themselves in 



