226 KAMBLES OF A NATURALIST. 



the animal, while the other throws off the exhausted 

 water, which collects in its passage the residue of 

 digestion. Thus, in the Teredo, the organs instead 

 of being placed side by side are arranged behind 

 one another, and this circumstance necessarily induces 

 important modifications in the form, proportions, 

 and general relations of these animals. Neverthe- 

 less, although this organisation may appear extremely 

 strange at first sight, it is fundamentally the same 

 as that of all the Acephala, and the philosophical 

 anatomist will have no difficulty in detecting in the 

 Teredo the essential character of the general type. 



When we examine the delicate and fragile shell, 

 the semi-transparent tissues, and the soft body which 

 is almost incapable of motion, we can hardly conceive 

 that the Teredo is an object to be feared ; and yet 

 this Mollusc is one of the most formidable enemies 

 of man. The Teredo attacks submerged wood some- 

 what in the same manner as the larvae of insects which 

 are vulgarly known as worms attack wood that has 

 been exposed in the open air. Imagine what would 

 become of our trees and furniture, and of the 

 supports and joists of our roofs, if they were to 

 be gnawed by worms measuring a foot in length. 

 If we supposed this for a moment we could better 

 understand the damage which these obscure miners 

 perpetrate by their stealthy and silent operations. 

 In a few months, or even a few weeks, thick planks 

 or piles of the strongest oak or pine, which to all 

 appearance are perfectly sound, are sometimes found 

 to be so completely excavated that, unable to offer 

 further resistance, they yield to the slightest shock. 



