TOUCH. 389 



in all directions, as if bewildered, and uncon- 

 scious of what they were doing. Some of their 

 companions were seen to notice their distress, 

 and approaching them with apparent compas- 

 sion, applied their tongues to the wounds of the 

 sufferers, and anointed them with their saliva. 

 This trait of sensibility was repeatedly witnessed 

 by Latreille, while watching their movements 

 with a magnifying glass. 



The Arachnida, from the mobility of their 

 limbs, and the thinness of their cutaneous invest- 

 ment, have a very delicate sense of touch. 

 Among the Mollusca, it is only the higher orders 

 of Cephalopoda that enjoy this sense in any con- 

 siderable degree, and they are enabled to exer- 

 cise it by means of their long and flexible ten- 

 tacula. Many bivalve mollusca have, indeed, 

 a set of tentacula placed near the mouth, but 

 they are short, and of little power. It is pro- 

 bable that the foot may also be employed by 

 these animals as an organ of touch. 



Fishes are, in general, very ill-constructed for 

 the exercise of this sense, and their fins are used 

 for no other purposes than those of progressive 

 motion. That part of the surface which pos- 

 sesses the most acute feeling is the under-side, 

 where the integuments are the thinnest. The 

 chief seat of the sense of touch, however, is the 

 lip, or end of the snout, which is largely sup- 

 plied with nerves ; and perhaps the cirrlii, or 



