48 TRANSACTIONS, NATURAL HISTORY SOCIETY OF GLASGOW. 



about half-tide, as in the last experiment. In less 

 than half-an-hour they were all dead. 



In the first experiment, it is probable that those 

 which died so soon had recently come up from a 

 lower zone of the tidal belt ; and having been less 

 exposed to a mixture of fresh water, they were less 

 able to bear the sudden change. This result is con- 

 firmed by the experiment with those taken from 

 very low tide, which rapidly succumbed when placed 

 in fresh water. 



These experiments show that while those speci- 

 mens taken from sea-water suddenly succumbed to 

 the influence of fresh water, yet, by getting up 

 the stream by degrees, they appeared to acquire 

 the power of living in nearly fresh water for a 

 considerable time. If all other conditions were 

 favourable, there can be little doubt that they 

 could be gradually brought to live in purely fresh 

 water. Nothing could be better for such experi- 

 ments than such a little fresh-water stream passing 

 down over their habitat, where they can come up, 

 sheltering under the sand, bit by bit, as they feel 

 disposed, to where the tide covers them at shorter 

 and shorter intervals, till the water is almost 

 fresh. 



Bathyporeia Robertsoni, Spence Bate and West- 

 wood. — There can scarcely be any doubt that this 

 is the male of Bathyporeia pilosa. It is generally 

 rather smaller, having long under - an tennse. The 

 males occur in much fewer numbers than the 

 females : in my experience not more than one to 

 twelve. There is also another variety with long 

 under-antennsB, but the flagellum is closely ringed. 

 The eyes of both male and female are oval and 

 dark red, becoming black in spirits. 



The female of this species "was first taken at 

 Wisby, on a sandy bottom, from 18 to 20 fathoms, 

 by Professor Lindstrom. It has been taken by 

 Professor Williamson on a fine sandy bottom off 

 Weymouth," and by Mr. Webster near Tenby. 



