CRUSTACEA OF NEW ZEALAND. 183 



been made do not confirm tliis hypotliesis at all, as floods in the river never aff'oct the 

 height of the water in the wells, while heavy rain makes them rise, and a continuance 

 of dry weather makes them fall. The absence of subterranean Crustacea appears to 

 confirm the opinion that the water of the artesian wells is not derived from the leakage 

 of the Waimakariri, for the water in which they are found at Eyreton is almost certainly 

 derived, partly at any rate, fi-om the Waimakariri, and if they exist there we might 

 reasonably expect to find them distributed all over the water affected by leakage from 

 that river. 



All the subterranean Crustacea hitherto collected from the underground waters of the 

 Canterbury Plains have been obtained by means of the ordinary suction-pumps with 

 which the w^ells are usually fitted. In the same way similar Crustacea have been 

 obtained in England by Spenco Bate and others, in France by Moniez, in various parts of 

 Europe by numerous observers, and in North America by Hay, Forbes, and others. In 

 Europe and North America these Crustacea have also been procured from underground 

 streams in caves and from the deep u aters of lakes, but none have as yet been ol)tained 

 in this way in New Zealand. These situations have not yet been properly searched, and 

 it is qiiite possible that the blind Crustacea may yet be obtained by exploring the caves 

 in different parts of the colony, and by dredging in the deep alpine lakes of Otago. 



The pumps referred to are mostly ordinary suction-pumps, and consequently do not go 

 down to a depth of much more than 30 feet. In some cases, however, owing to a con- 

 tinuance of dry weather for several years, the pipes have had to I^e driven deeper, and 

 fitted with a cylinder-pump, and Crustacea have still been occasionally taken from them ; 

 but it would be obviously rather more difficult to ])riug up Crustacea from greater 

 depths in this way than from less depths by an ordinary suction-pump, even although 

 they were equally numerous in the waters underground in the two cases. In some cases 

 there is an actual well, the soil having been excavated to a depth of 25 feet or so, and a 

 hole thus formed in which the water can accumulate; in the majority of cases, however, 

 the suction-pipe has been simply driven into the ground like that of an ordinary artesian 

 w^ell. The Crustacea are obtained quite as freely from wells of the one description as of 

 the other. I have myself noticed that the Crustacea are often brought up most abundantly 

 when pumping is first commenced, and that jerking tlie handle of the pump somewhat 

 violently is often more successful than pumping at the ordinary rate. Mr. J. B. Mayne 

 has noticed the same thing in connection with pumps at Ashburton, and Mr. E. 

 Wilkinson, of Lincoln, states that the Crustacea come up most abundantly after the 

 pump has been left for a time, especially in the early morning. Of course, these facts 

 can be easily accounted for if we consider the character of the small animals with which 

 we have to deal, for a sudden upward flow of the water would be more likely to carry them 

 with it than a more gradual flow, and they would be more likely to be found in the 

 neighbourhood of the pipe, or indeed in the pipe itself, when the waters had been for 

 some time undisturbed by pumping. 



In order to collect them I have generally taken a small hand-bowl, pumped it full by a 

 few vigorous or jerking motions of the handle, then examined it to see if any Crustacea 



