20 THE HISTORY OF AQUARIA. 



gallons more. The salt water thus obtained, how- 

 ever, is liable to be very turbid. This huge quantity 

 takes about ten hours to be pumped in. In the chief 

 corridor above mentioned the number of tanks is 

 twenty-one. The total frontage of all is about 740 

 feet. Octagonal table tanks are also exhibited, in 

 which the rarer marine zoophytes, &c., are kept, 

 and where the process of fish-hatching may be seen 

 going on. 



The most important event which has taken place 

 in the history of aquaria, from a purely scientific 

 point of view, was undoubtedly the founding of the 

 aquarium at Naples by Dr. Dohrn, a German 

 naturalist, Mr. Lloyd aiding in its construction. The 

 expense was borne almost entirely by himself and 

 a few personal friends, but the result has been 

 scientifically successful. Dr. Dohrn's idea was to 

 make it a kind of zoological station for the ob- 

 servation of the life-histories of marine animals 

 analogous to astronomical observatories or stations. 

 The ground floor of the building covers 8000 feet, 

 there being a story above fitted up as a zoological 

 dissecting room and laboratory, for the use of natu- 

 ralists. Further, Dr. Dohrn here receives students 

 of natural science, the animals examined being ob- 

 tained by dredging expeditions which are carried on 

 from time to time. A certain number of students' 

 " tables" were offered to various Government scientific 

 societies at a fixed sum. Some of these were taken 



