304 



CHELUEA AND LIMNORIA. 



native of our shores is what is now called T. norvagicus, 

 the T. navalis of most British writers, though not of 

 Linnseus. This species is of large size, and as active in 

 mischief as the true navalis. Mr. Thompson gives an 

 interesting account of the rapidity with which it has 

 destroyed wood-work in the harbour of Port Patrick ; 

 and, according to Mrs. Griffiths, the same species caused 

 the destruction of the bridge at Teignmouth. It has 

 been observed on various other parts of our coast, en- 

 gaged in its constant task, reducing beams of timber 

 to dust, and undoing with persevering industry what 

 the "lord of the creation" is at most pains to do. 



SELDBA AND 



In this task of undoing, the Teredo does not work 

 alone. The wood-work that escapes his auger may fall 

 to powder under the teeth of two minute Crustaceous 

 animals (Limnoria terebrans and Chelura terebrans), not 

 so big as a grain of rice, but as active as " the mother 

 of mischief" herself, and as tmtiring. These little 



