AMPHIPODA AND ISOPODA OF THE FIRTH OF CLYDE. 15 



"The belt of sand they usually occupy at high- 

 water is above the ordinary tide -mark, whereby 

 in continuous wet weather they must be exposed to 

 a considerable amount of fresh- water. To test how 

 long they could live in that element, two were put 

 into a cupful of rain-water, where they swam about 

 freely for a time. By three hours they were lying 

 on their backs, but when disturbed they made efforts 

 to swim and to stand on their feet, which they only 

 did for a very short time. When taken out of the 

 water they could still walk and leap a little. At 

 this stage one was laid on sand damped with sea- 

 water, and after a little while it recovered, and 

 burrowed into the sand. The other, after five hours' 

 immersion, ceased to live. From this experiment 

 they appear to be able to bear much drenching 

 under heavy rain, where the water drains quickly 

 through the sand ; yet we find that a few hours' 

 close confinement in fresh-water is destructive to 

 life."* 



As this species is said never to be found volun- 

 tarily inhabiting the sea, to test how long they 

 could live in salt-water twelve of them were put 

 into a glass jar with about a pint of sea- water. 

 They seemed at home for two or three days, but by 

 the sixth day had begun to become somewhat 

 languid. Although the experiment could not satis- 

 factorily be carried further in the absence of food, 

 it showed that they were fitted against any contin- 

 gency of rain or flood that was likely to overtake 

 them in their natural haunts. 



Genus Orchestia, Leach. 



ORCHESTIA GAMMARELLUS, Pallas. 



Oniscus gammarellus, Pallas, Spicil. Zool., fasc. ix. 

 (1772), tab. 4, fig. 8. 



Cancer gammarellus, Herbst, Versuch einer Natur- 

 gesch. der Krabben und Krebse (1782-1804). 



* Trans. Nat. Hist. Soc. Glasg., vol. i., p. 130. 



