122 COMPARISONS OF STRUCTURE IK ANDIALS. 



loss — it has been supposed that some peculiar 

 sense resides in them, to us totally unknown. 

 Be this as it may, we cannot doubt that they 

 are the organs of touch, and are extremely 

 important; and that the insect is bewildered 

 and incapable of exerting its instincts when 

 they are removed. 



Besides the sense of touch, that of hearing 

 also appears to reside in the antennae of insects, 

 or is probably seated in some organ at their 

 base. We say probably, for the question is 

 still at issue ; and though most naturalists 

 allow that insects hear, (for by various sounds 

 many make signals to each other,) yet all do 

 not agree as to the situation of the organ of 

 hearing. In some moths, Treviranus discovered 

 a sort of drum at the base of the antennse, be- 

 hind which were nervous fibrils derived from 

 those supplying the antennae ; in other insects, 

 however, such an apparatus cannot be detected. 

 It is remarkable, however, that in the lobster 

 and higher Crustacea, the organs of hearing ai'e 

 situated at the base of the larger antennae, on 

 the under side, where a tympanic membrane 

 may be seen stretched across a little pit, having 

 a slightly elevated margin. This cell or pit 

 is filled with fluid, and a b];anch given olT 



