PICTET's PALJEONTOLOGY. 51 



true in a very vague sense, but I believe totally inadmissible if we 

 give it a distinct meaning, and assume that all created beings are 

 connected by any single or continued series. It is indeed impossible 

 to place all existing animals in such an order that we can success- 

 ively pass from one species to another, each gradually decreasing in 

 perfection ; but as we cannot here enter fully into the consideration 

 of this theory, which is one familiar to all zoologists, 1 will content 

 myself with quoting two groups of numerous facts which are op- 

 posed to it. On the one hand there are classes of animals so com- 

 pletely detached, that they have nothing to connect them with the 

 rest, thus creating in this imaginary series very important breaks of 

 continuity ; and on the other hand, there are types of organization 

 which are absolutely indivisible, and such, that while their more per- 

 fect forms are superior to those of another class, the less perfect are 

 inferior, as is the case with regard to the Mollusca and Articulata, 

 the former being superior to the latter in the Cephalopoda but in- 

 ferior in the Acephala, so that we cannot arrange the mollusca and 

 articulata in any continuous series. It is also the case that these 

 types have different kinds of perfection according as the conditions 

 of a certain kind of organization are realized, so that it is extremely 

 difficult to bring them into comparison. The highest molluscous, 

 articulated, or radiated animal is each characterized by a different 

 sort of perfection, which precludes us from deciding on its relative 

 superiority to the others. 



"We do not therefore admit the scale of beings as the starting-point 

 in the discussion of this law, and it appears to us that the true idea 

 of the relative perfection of the organization of different animals is 

 the following: — These beings are divided into a certain number of 

 groups, each of which exhibits a peculiar type ; but while some of 

 the groups are manifestly superior to others when we consider their 

 organization generally, it happens also that the result of a compa- 

 rison sometimes fails to establish any real superiority. The most 

 perfect type is that of the Vertebrafa, which must evidently be placed 

 far at the head of all the inferior groups. It is itself divided into 

 four other types exhibiting very unequal degrees of perfection of 

 organization. The mammalia are more perfect than the birds, and 

 the birds than the reptiles, while the fishes are in this view the most 

 imperfect. But in the invertebrata the distribution is by no means 

 the same, and the principal classes, the Mollusca, the Articulata and 

 the Jiadiata, are superior or inferior to one another according to the 

 point of view under which we regard them and the species which 

 we compare, so that we are no longer able with them, as with the 

 vertebrata, to arrange them in a series, wliere the most imperfect of 

 the first group is superior to the most perfect of the second. Each 

 type again of the invertebrata subdivides itself unequally, although 

 these subdivisions might, more properly than the principal group, 

 be arranged in continuous seri(;s. 



" If now, in comparing different creations, we apply these views, 

 less simple it may seem and perhaps more vague, but probably also 

 more correct than the others, we shall find, in the first place, that the 



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