LIMACID.^. 125 



Family I. LIMACID.E. 



Body long, straight, and flexible : mantle covering only the 

 upper part of the back, and forming a shield : head prominent : 

 tentacles 4, cylindrical, arranged in pairs, the upper pair being 

 the longest : eyes 2, placed on bulbs at the tojD of the upper 

 tentacles : foot united to the body and coextensive with it. 



Shell either rudimentary and of an indefinite form, or 

 shield- shaped, placed underneath the mantle. 



I do not propose to treat of this family aud its com- 

 ponent members to the same extent as my opportmiities 

 have enabled me to do with respect to the testaceous 

 members of the same Order ; and I must admit that I 

 have not paid equal attention to this part of the subject. 

 The aspect^ and much less the handling, of these slimy 

 creatures cannot be considered as especially inviting ; 

 and as I believe the majority of my readers share in this 

 opinion, I may with greater confidence ask their indul- 

 gence for any shortcomings on this point. At the same 

 time I would observe that the subject offers, to those 

 who are inclined to pursue it, a wide field of research 

 and a greater prospect of novelty than can be expected 

 from the study of the testaceous Mollusca. The ana- 

 tomy, physiology, and habits of the Slugs were described 

 nearly two centuries ago by our countryman, Dr. Lister, 

 in his admirable treatises on British animals ; and Mr. 

 Nunneley and the Rev. B. J. Clarke have lately done 

 much to increase our knowledge of these mollusks. Some 

 of their remains have been detected in our upper ter- 

 tiary beds at Copford, as well as in similar deposits in 

 the South-west of France. 



