32 



THE DOCTRINE OF DESCENT. 



Cuvier believed them to be more nearly related, and in- 

 cluded them altogether; under the name of Radiata. This 

 similarity, however, is only superficial, for whilst, on the 

 one hand, anatomy discloses the great difference of the 

 Coelenterata and Echinodermata, the history of evolution 

 still more decidedly banishes the Echinodermata from 

 this position, and connects them more closely with the 

 next division. 



In this, that of the Vermes, the systematizer of the 

 old school finds his real difficulty; in so many ways do 

 they deviate from each other, so great is the distance 

 between the lower and the higher forms; and after de- 

 ducting the distinctive marks of orders, so little remains 

 as a common character, so variegated is the host of 

 smaller scattered groups, and even of single species, 

 which demand admittance to the system of the Vermes. 

 If we attempt to describe their typical nature in a few 

 words, it must be something like this: The Vermes are 

 more or less elongated, symmetric animals, which possess 

 no actual legs, but effect their locomotion by means of a 

 muscular system, closely combined with the integuments, 

 which frequently become an actual muscular cylinder. 

 To this we will add, that the perplexities and difficulties 

 in reference to points of classification are transformed 

 into sources of knowledge for the adherent of the doc- 

 trine of Descent. 



The relations of the previous family with the type of 

 the Articulata is so conspicuous, that the " kinship " 

 of the two was never questioned, even by the older 

 zoologists. The very name of one, the highest division 

 of the Vermes, that is, of the Annelids, or segmented 

 worms, indicate this connection. This distinctive mark 



