16 TEANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



a couple of gallons of fresh sea- water being added to the 

 system every day. 



During the period when the apparatus was working the 

 temperature and the specific gravity of the water in the 

 tanks kept fairly constant, the extremes of the range 

 being : — 



Temperature from 50° to 53° F., and 



Specific gravity from 0*0265 to 0*0270. 



Each of the three tanks had a partition 1 foot from its 

 outflow end which stopped 2 inches from the top, and a 

 second partition 6 inches nearer the end, which reached 

 the top but stopped short 2 inches from the bottom of the 

 tank. In the two compartments imperfectly separated by 

 this last partition, clean washed sand was placed so as to 

 reach to about 4 inches from the bottom. Consequently 

 all water escaping from the tank had to flow over the 

 first partition and under the second, filtering through the 

 bed of sand as it went. The object of this was to form 

 a sand trap which would let the water pass through, but 

 keep back the suspended fish eggs and embryos. By this 

 method the same water can be used to circulate through 

 several tanks containing different kinds of embryos. 



A more detailed account of these fish-hatching experi- 

 ments at Port Erin will be given in the Annual Report 

 of the Sea-Fisheries Laboratory to the Lancashire 

 Committee. 



Dredging Expeditions. 



Since the last report, the Committee have organised 

 eight dredging expeditions, nearly all in steamers, as 

 follows : — 



I. November 24, 1895. — Small boats. Localities 

 dredged : — Port Erin Bay, in depths up to 7 fathoms. 



II. February 2, 1896. — Hired steamer 'Rose Ann.' 



