20£ ON THE ANIMAL KINGDOM. 



This last division I propose to name ACRITA. 

 On considering the gelatinous composition of these ani- 

 mals, the dispersion of the nervous molecules through 

 their substance, and the absolute certainty that they are de- 

 stitute of every sense except perhaps those of taste and 

 touch, we are led to connect them with the Mollusca, whose 

 substance is always mucous and often even gelatinous — 

 whose nervous system, though collected into several gan- 

 glions, or centres of sensibility, has nevertheless these gan- 

 glions dispersed with little if any arrangement throughout 

 the whole mass of their body — and whose senses, so far at 

 least as we are certain of their existence, seem to be con- 

 fined to those of taste and touch, with the exception of a 

 few animals of the division which possess the organs of 

 sight, and still fewer which possess those of hearing. 



Nevertheless, on comparing the Acrita with the Mol- 

 lusca, we find that the organization of these last has be- 

 come much more complicated, and that a distinct system 

 of circulation and peculiar organs for respiration, di- 

 gestion, and secretion are even visible in these animals, 

 which connect them in a remarkable manner with a still 

 more perfectly organized family — the Pertebrata. 



These however by their red blood, their muscular heart, 

 their jaws acting vertically, their distinct organs for sight, 

 hearing, smell and taste, their sexes constantly distinct, 

 their vertebral column and extreme concentration of the 

 nervous system, are sufficiently insulated from the Mol- 

 lusca, as well as from all other material beings. The group 

 is therefore perfectly distinct and natural ; yet if we at- 

 tempt to define it by any one of the abovementioned various 

 properties, little examination is requisite to convince us 

 that the characteristic thus chosen either disappears in 



