14 A HISTOEY OF RECENT CEUSTACEA 



any stint of numbers. Less commonly the innocent well- 

 shrimps, which are also amphipod crustaceans, may be 

 obtained from wells. It may be proper to mention that 

 the well-shrimp is not poisonous, and that it flourishes in 

 water which is perfectly wholesome. A different view of 

 its character is probably entertained by many owners of 

 wells, who are on that account unwilling to mention or 

 acknowledge its presence. From stagnant ponds various 

 species of Entomostraca may be obtained in vast abund- 

 ance. Some of the Phyllopoda are found only in brine 

 pools. The brine shrimp, Artemia, breeds in vast num- 

 bers in the mud of the great Salt Lake of Utah. In 

 South America one of the Ostracoda very singularly dwells 

 on the leaves of a plant. The river crayfish and crusta- 

 ceans parasitic on freshwater fish are pretty widely dis- 

 tributed. Highest in known range of all the Crustacea 

 are the Isopods and Amphipods taken by Mr. Whymper at 

 a height of 13,300 feet on the Great Andes of the Equator. 

 In many parts of the world there are land-crabs, but none 

 of these live in the British Isles. This is referred to as 

 follows in the ' Narrative of the Cruise of the Challenger.' . 

 In describing the visit to Ascension Island in the South 

 Atlantic Ocean, the writer says : — 



' Land-crabs swarm all over this barren and parched 

 volcanic islet. They go down to the sea in the breeding 

 season ; they climb up to the top of Green Mountain, and 

 the larger ones steal the young rabbits from their holes 

 and devour them. It always seems strange to an English 

 naturalist to see crabs walking about at their ease high up 

 in the mountains, althoijgh the occurrence is common 

 enough and not confined to the tropics. In Japan a crab 

 is to be met with walking about on the mountain high 

 roads far inland, at a height of several thousand feet, as 

 much at home there as a beetle or a spider, and crabs of 

 the same genus (Thelphusa) live inland on the borders of 

 streams in Greece and Italy.' 



Prance and Germany, as well as England, have reason 

 to regret that the sunny south should have a monopoly of 

 these land or river crabs, for they are delicate eating and, 



