OBSEEVATIONS ON WORMS.* 



THE different kinds of worms, as they may be 

 called in a general way, inhabiting the land or fresh- 

 water, appear to be numerous : yet they have re- 

 ceived but little attention from naturalists, at least 

 from the naturalists of this country. They whose 

 inclinations have led them to the study of these 

 tribes, have for the most part restricted their atten- 

 tion to the marine species, which doubtless are more 

 attractive from their larger size, and greater variety . 

 Nevertheless, those abovementioned are not without 

 interest, and would repay a careful investigation of 

 their characters and history. Those found free, that 

 is, not inhabiting the bodies of other animals, belong 

 principally to the old genera of Lumbricus, Nais, Gor- 

 dius, Hirudo, and Planaria, which have been since 

 divided into several others. Some of those common 

 in ponds, though not strictly parasitical, are often 

 found infesting the shells of certain fresh-water 

 molluscks, more particularly the Physa fontinalis, 

 Paludina vivipara, and Planorbis marginatus, which 

 appear particularly to suffer from their attacks, 

 wriggling much about in the attempt to rid them- 

 selves of their enemies, which creep round them, 

 and adhere very closely to their soft parts. It seems 



* Comprising the two groups of Annelida and Entozoa of 

 modern naturalists. 



