12S THE PHILOSOPHY 



Becaufe thefe tails have feme refemblance to that of a rat, 

 he diftingulfhes the animals by the name of rat-tailed luorms, 

 Thefe worms are aquatic, and never appear on dry ground 

 till they are about to undergo their firil transformation. 

 Reaumur, in order to obferve their oeconomy more clofely, 

 collected a number of rat-tailed worms, and put them into a glafs 

 velTel filled two inches high with water. At firfl they were 

 conflderably agitated,' each feemingly fcoirching for a proper 

 place of repofe. Some of them fwam acrofs^ others attached 

 themfelves to the fides, and others refled at the bottom of 

 the vefTel. In a quarter of an hour they were almofl: entirely 

 tranquil, and Reaumur foon difcovered the real ufe of their 

 long tails. Upon examining the vefTel, he found that each 

 of the animals; in whatever lituation they were placed, ex- 

 tended its tail exa<5lly to the furface j that, like other aquatic 

 infecTtB, t\x<i refpiration of air v^'as neceffary to their exifl- 

 encQ ; and that the tail, which is tubular, and open at the 

 extremity, was the organ by which this operation was per- 

 formed. In this experiment, the difiance from the bottom 

 to the furface was two inches, and, of courfe, the tails were 

 of an equal length. To difcover how far the animals could 

 extend their tails, this mofl ingenious and indefatigable phi- 

 lofopher gradually augmented the height of the water, and 

 the tails uniformly rofe to the furface till it was between five 

 and fix inches high. When the water was raifed higher, 

 the animals immediately quitted their flation at the bottom, 

 and either mounted higher in the water, or fixed upon the 

 fides of the vefTel, in fituations which rendered it conve- 

 nient for them to reach the furface with the points of their 

 tails. Thefe tails confift of two tubes, both of which are 

 capable of extenfion and contradion. The firfl tube is al- 

 ways vifible ; but the fecond, which is the proper organ of 

 refpiration, is exferted only when the water is raifed to a cer- 

 tain height. Through this tube the air is conveyed into 



