THE WORMS. 147 



The tliird tribe of the animal kingdom, the })hylum of 

 Worms or worm-like animals (Vermes, or Helminthes), con- 

 tains a number of diverging branches. Some of these 

 numerous branches have developed into well-marked and 

 perfectly independent classes of Worms, but others changed 

 long since into the original, radical forms of the four higher 

 tribes of animals. Each of these four higher tribes (and 

 likewise the tribe of Zoophytes) we may picture to ourselves 

 in the form of a lofty tree, whose branches represent the 

 different classes, orders, families, etc. The phylum of Worms, 

 on the other hand, we have to conceive as a low bush or 

 shrub, out of whose root a mass of independent branches 

 shoot up in different directions. From this densely 

 branched shrub, most of the branches of which are dead, 

 there rise four high stems with many branches. These 

 are the four lofty trees just mentioned as representing the 

 higher phyla — the Echinoderma, Articulata, ' Mollusca, and 

 Vertebrata. These four stems are directly connected with 

 one another at the root only, to wit, by the common primary 

 group of the Worm tribe. 



The extraordinaiy difficulties which the systematic ar- 

 rangement of Worms presents, for this reason merely, are 

 stUl more increased by the fact that we do not possess any 

 fossil remains of them. Most of the Worms had and still 

 have such soft bodies that they could not leave anj' 

 characteristic traces in the neptunic strata of the earth. 

 Hence in this case again we are entirely confined to the 

 records of creation furnished by ontogeny and comparative 

 anatomy. In making then the exceedingly difficult at- 

 tempt to throw a few hypothetical rays of light upon the 

 obscurity of the pedigree of Worms, I must therefore 



