250 SUPPLEMENT 



appears to approve the system of Baster and Dumeril respect- 

 ing the position of the organs of smell in insects, says nothing 

 particular with regard to the Crustacea. M. de Blainville, in 

 his last work, adopts as most probable, the opinion tliat the 

 antennae are the seat of smell in all the articulated animals, 

 because it is in accordance with many considerations a 'priori. 

 He thinks that in the invertebrated animals, the apparatus of 

 olfaction presents this difference to what takes place in ver- 

 tebrated animals : that the skin, more or less modified, no 

 longer lines a cavity or pouch, lodged in the head ; but that 

 it clothes the extremity of the appendages which may project 

 more or less in front of the animal, such as the antennae or 

 tentacula. 



Of the four antennae, which exist in the Crustacea, M. de 

 Blainville seems to think that the seat of smell resides rather 

 in the two intermediate, than in the two exterior. 



There can be no sort of doubt that the sense of taste exists 

 in the Crustacea, and it appears probable that its seat is 

 placed at the commencement of the intestinal canal; for we 

 find that some of the nervous threads which are furnished by 

 the two cords surrounding the oesophagus, proceed to this 

 part. Nevertheless, one might also suppose it to be in the 

 flagelliform palpi, which are annexed to the back of the jaw- 

 feet, just as it was, for a long time, admitted to exist in the 

 maxillary and labial palpi of the insects ; but these palpi of 

 the Crustacea are by no means conformed for the perception 

 of savours, and are not even organs of tact. They can be con- 

 sidered as nothing but true appendages of locomotion, a little 

 modified, and which can serve at most only to direct the prey 

 towards the jaws. 



Touch would appear to be an extremely obtuse sense in the 

 majority of the animals of this class. The very name of 

 Crustacea sufiiciently indicates that their skin, the ordinary 

 seat of this sense, is hardened, and changed into a truly solid 



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