ter station at such a distance from the water. Was 

 it determined in its choice of that place by the mere 

 accident of finding the potatoes which were planted 

 there ? or is it the practice of the aquatic rat to for- 

 sake the neighbourhood of the water in the colder 

 months ? 



Though 1 dehght very little in analogous reason- 

 ing, knowing how fallacious it is with respect to nat- 

 ural history ; yet, in the following instance, I cannot 

 help being inclined to think it may conduce towards 

 the explanation of a difficulty that I have mentioned 

 before, with respect to the invariable early retreat of 

 the Hirundo ai^us, or swift, so many weeks before its 

 congeners ; and that not only with us, but also in 

 Andalusia, where they also begin to retire about the 

 beginning of August. 



The great large baf^ (which by the way is at 

 present a nondescript in England, and what I have 

 never been able yet to procure) retires or migrates 

 very earlv in the summer: it also ranges very high 

 for its food, feeding in a different region of the air ; 

 and that is the reason I never could procure one. 

 Now this is exactly the case with the swifts, for they 

 take their food in a more exalted region than the 

 other species, and are very seldom seen hawking for 

 flies near the ground, or over the surface of the 



* The little Bat appears almost every month in the year ; but I have 

 never seen the large one till the end of April, nor after July. They are 

 most common in June, but never very plentiful. 



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