Mr. Rennie on the Cleanliness of Animals. 27 



swine, which I have discovered to be peculiarly cleanly ; I 

 refer to the several species of spiders. During the course of 

 a series of observations and experiments on the process by 

 which they can shoot lines of their gossamer silk across a brook, 

 or other intervening obstacle, it was indispensable that I should 

 pry with minute attention to their every movement ; and I 

 was soon struck with one which interested me not a little, in 

 the instance of one of the long bodied species, (Tetracjnatha 

 extensa, LATREJLLE.) It appeared to be mumbling, if I may 

 use the term, its legs between its mandibles, drawing each 

 leisurely along, as a dog may be seen to gnaw a bone when not 

 very much in earnest, but more by way of pastime than of 

 making a dinner. I could not at first account for this ; the 

 ancient naturalists, who drew largely on their imagination when 

 facts failed them, would at once, I have no doubt, have leapt to 

 the conclusion, that the spider, in default of prey, actually 

 devoured its own legs, as it has been asserted to do its web*. 



A little attention convinced me, that the movements alluded 

 to were precisely 1 of the same kind as the preening of birds. 

 Spiders have their legs more or less covered' with sparse hair, 

 which, being rather long and bristly * is apt to catch up bits of 

 their own web and other extraneous matters, and these, from 

 the delicacy of their semi-transparent skin, must produce un- 

 comfortable irritation. To free themselves from this is one of 

 their daily occupations ; and when a spider appears to the less 

 minute observer to be quite at rest, it will often be seen, on 

 close inspection, to be assiduously and slowly combing its legs 

 in the manner I have above mentioned. The term combing is 

 very appropriate in the instance of the common garden-spider 

 (Epeira diadema), which is furnished with a set of teeth some- 

 what in form of a comb; but it has another instrument in 

 addition to this, peculiarly useful in the process, consisting of a 

 smooth and somewhat curved horny needle, which bends over 

 the teeth of the comb, and holds the limb which it is dressing 

 more firmly down, as if, after entering it in the hair, we were 

 to apply a finger over the edge of one of our artificial combs. 

 In some other spiders (Dysdera erythrina, &c.), there is, in 

 the situation of the comb just described, a closely set brush of 



* BLOOMFIELD'S Remcuns y vol. ii. 



