NATURE OF PLANARIJE. S 



farther, lest, in obscuring the fragility of 

 their texture, we may be erroneously led to 

 deem them, of all others, the chosen works 

 of the universe. 



Animals with soft bodies, wanting bones, 

 are divided into several subordinate tribes, 

 one of which, either from external configu- 

 ration, or a smooth gliding motion over even 

 surfaces, has been denominated Planaria. 

 All the species with which we shall be oc- 

 cupied are strictly aquatic ; the presence 

 of water is equally irftlispensible to their 

 safety and preservation ; for contact of the 

 atmospheric element, though during the 

 shortest period, is irremediable destruction. 

 Some dwell in the sea ; others inhabit lakes, 

 marshes, and such streams as are almost still 

 or undisturbed: and it is also said that 

 they may be found in humid meadows ; 

 but none of that description have come 

 within the sphere of my research. 



Perhaps the genus is as yet insufficient- 

 ly characterized ; nor will the subsequent 

 remarks do more than approximate it to its 



