Manchester Memoirs, Vol /vizi (igi^), No. t. 3 



to the blood-system would be indispensable before any 

 conclusions can be arrived at. 



T/ie luunersion of Ligia in Fresh and Salt Water. 



The first experiments were carried out upon a number 

 of specimens which were obtained from Swanage early in 

 November ; these were large forms, and in a very healthy 

 condition. Of these, three were taken and placed in a 

 vessel containing fresh pond -water, in such a way that 

 they were continually immersed, and were closely observed 

 for a time ; simultaneously, a second batch was placed in 

 a vessel of sea-water. 



The specimens in fresh water swam about rapidly at 

 first, and exhibited signs of considerable activity ; later, 

 they settled down and moved about on the bottom of the 

 vessel with their usual characteristic motion, but otherwise 

 did not seem to be in any way affected by their changed 

 surroundings. 



The following morning, after immersion for 24 hours, 

 one was dead, but the other two still survived and were 

 apparently quite normal ; on the next day, however, they 

 became very sluggish, sank into a dormant condition and 

 eventually died. 



On examination of the gills it was found that in all 

 three cases the endopodites, or inner lamellae of all but the 

 first pair, were considerably swollen and distorted. The 

 expodites, however, were unaffected. 



Of the three specimens in sea-water, all appeared 

 normal and unaffected by the change during the first day, 

 but at ten o'clock the next morning they were found to 

 be dead. 



A second batch, from the same collection, was again 

 placed in sea-water, but these also succumbed after an 

 immersion of eight hours This would seem to indicate 



