316 OBSERVATIONS ON WORMS. 



trial animal ; though it cannot exist without much 

 moisture. 



The ground fluke is from half to three quarters of 

 an inch in length. Its form is an elongated oval, 

 when the body is stretched out for motion : but the 

 latter is capable of great contraction as well as ex- 

 tension ; and, when at rest, is gathered up into a 

 small compass, as in the leech. Above, it is slightly 

 convex ; beneath, flat. The skin is viscid and opake, 

 and of a dusky or greyish colour, darker in some 

 individuals than others. When the body is con- 

 tracted, it appears slightly annulose, or the surface 

 compassed by fine ring-like striae. The anterior 

 part can only be distinguished from the posterior 

 when the animal is in motion. There are two small 

 black eye-like points at the anterior extremity, but 

 they are not discernible, except when the animal is 

 on the stretch, so as to attenuate the skin ; and not 

 then without the help of a strong lens. As the 

 animal advances, it leaves a slimy track behind it, 

 like a slug ; and (as Miiller observes) it might easily 

 be mistaken for a young slug at first sight. 



Miiller mentions having met with this creature in 

 September and November. I have observed it prin- 

 cipally in the spring, but believe that it is to be 

 found at most seasons of the year, when there is 

 sufficient moisture in the soil and surrounding at- 

 mosphere to bring it into activity. I have not been 

 able to satisfy myself entirely in respect of its food ; 

 but I am strongly inclined to believe that it is car- 

 nivorous, feeding principally upon the smaller land 

 mollusks, especially those species which inhabit the 



