On the Sense of Feeling. 297 



When the autennfe are removed, the faeulties of the insect seem to be 

 for the time destroyed. It is unable to walk or fly^ or if it attempts to do 

 so, is evidently bewildered. In the case of bees and ants, whose habits 

 have been more accurately examined than those of most other insects, the 

 utility of the antennae is very remarkable, and has given rise to the opi- 

 nion that they are the organs of more senses than one. 



The trunks or probosces of the diptera, flies, etc. and the peculiar 

 structure called the nether lip, were supposed by Cuvier to be organs of 

 touch : but in all such speculations it should be borne in mind, that, al- 

 though it may be experimentally proved that certain senses are possessed 

 by insects, the exact seat of each of them is by no means so apparent. 



Although the vital organs in insects are far less complex than in the 

 mollusca, beneath which they are accordingly placed, yet in the develop- 

 ment of the senses, and of what may fairly be called the social faculties, 

 they are unquestionably superior. Who, indeed, unacquainted with his 

 minute anatomy, would suppose the bivalve mollusca, the oyster for ex- 

 ample, to be higher in the animal scale than the ant or the bee. 



The arachnida or spider tribe have long been famous for the accuracy 

 of their tact, as might indeed, from the length and mobility of their limbs, 

 and from the exquisite delicacy of their cutaneous mantle, have been ex- 

 pected ; their sensitive powers approach closely those of the insects, the 

 tribe, above which, they form. 



In the molluscous animals it is difiicult to separate the regular integu- 

 ment from the subjacent cellular tissue; the different parts of the skin here 

 however begin to be apparent, and the pigment or rolouring matter is es- 

 pecially distinguishable. The cryptic apparatus in these animals is well 

 developed, and all must have had occasion to observe the quantity of the 

 mucous secretion, in the traces of the slug or snail. They do not possess 

 hair, nor any thing analogous to it. 



In many of the mollusca, as the slug, this integument completes their 

 covering, and such are termed naked ; but in others, a calcareous secretion 

 is deposited in the structure of the skin, and forms what is familiarly 

 known to us as the shell. 



Although the general flexibility and softness of the surface of the mol- 

 lusca might seem to indicate a favourable disposition for the apprehension 

 of bodies, the sense of tact does not often appear to be possessed by them 

 in any very high degree, nor do we find any very remarkable apparatus for 

 the exercise of touch. 



In many of the acephalous mollusca, besides the digitations of the 

 mantle, are found others assuming somewhat of the appearance of tenta- 

 cula; and in some of the higher animals these tentacula are more fully 

 dcvclopcfi ; they have been supposed to be organs of touch. 



The muscular disks occupying the inferior parts of those mollusca, 

 whicli arc hence called gastcropodes, arc liighly organized and probably 



