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have no antennae, and grass-hoppers after these 

 have been removed. In all likelihood, it is in the 

 majority of insects merely a variety of touch, 

 and common, therefore, to the greater part of the 

 surface. In such insects as present any appear- 

 ance of a distinct auditory apparatus, as the cray- 

 fish, it is very similar in its structure to that of 

 the cuttle ; consisting, in like manner, of a bag 

 filled with liquid situated, in this instance, in a 

 bony cylinder at the root of the larger antennae 

 an auditory nerve expanded upon it, and some 

 pieces of earthy matter in the liquid which it con- 

 tains. In the cray-fish, however, unlike the cut- 

 tle, the bag in question is not surrounded on all 

 sides by the hard mass which contains it, but is, 

 near the surface of the body, in contact with a 

 thin membrane the first approach to the exter- 

 nal parts of the auditory apparatus, as met with 

 in the higher tribes of animals. 



Nor is the auditory apparatus of most fishes 

 much less simple than that of the invertebral 

 animals. The membranous bag, however, above 

 spoken of, is connected in general with three 

 semicircular canals, of a similar structure, and 

 furnishing more space for the distribution of the 

 auditory nerve ; and the earthy pieces, within 

 the liquid contained in this bag, have begun to 

 assume the appearance of regular bones. Still, 

 in most fishes all these parts are buried within 

 the skull, and send no process to the surface ; 

 in some of the cartilaginous tribes alone this bag- 

 being prolonged to the upper and back part of 



