Tanks No. 18 and 22. 
89 
the tins with which we are familiar; they are sold annually to the value 
of 10 to 15 millions of francs. The experiment has been made with 
some success of similarly treating the English Sardines. 
The whole genus Clupea is ill-suited for a life in captivity, and the 
Sardines will never be seen in the Aquarium; all the experiments to keep 
them there have resulted only 
in their rapidly losing their 
scales and dying. Visitors, 
however, will probably have 
an opportunity, during their 
stay in Naples, of recogniz¬ 
ing them in their fried con¬ 
dition at the dining table. 
A fish only found in the Fig- 163. Centriscus scolopax, I /2 nat. size. Tank 22. 
Aquarium at certain seasons 
is the Bellows-fish, also called the Trumpeter or Sea-snipe, Centriscus 
Fig. 163, tank 22). 
The peculiar order of Plectognathi are characterised by the possession 
of on immobile upper jaw and a spiny or armoured skin. They are almost 
all tropical forms; many, such as the Urchin-fish or Sea-hedgehog, the 
Globe-fish, and the Trunk-fish, usually well represented by dried specimens 
in Natural History Museums. The Bay of Naples contains two examples 
of this curious order of fishes; the Sun-fish, Orthagoriscus , and the 
File-fish, Balistes (Fig. 164). The former has up to the present been 
one of the greatest rarities of the Aquarium, and has rarely lived there 
longer than a week, so that we can give no interesting details of its 
habits. Balistes, however, is always present (in tank 18) from spring 
till winter, and is very remarkable; its short body being out of all pro¬ 
portion in height, and its mouth provided only with very few teeth. It is 
a lively fish, loving companionship, and endowed with great curiosity. It 
is, however, only in summer that it shews its real nature, and specimens 
