20 NEW-YORK FAUNA MOLLUSCA. 



FAMILY LIMACIDM. 



Body elongated, semicylindrical, flattened beneath. A wrinkled mantle on the anterior part 

 of the body in most species, sometimes covering the whole superior or entirely wanting 

 surface. In this mantle is occasionally found aflat shell, or more frequently a few calca- 

 reous grains. Two or four retractile tentacles ; the upper and posterior pair larger, 

 oculiferous. When only two tentacles, there is a pair of labial appendices. The pulmo- 

 nary cavity variously placed. The position of the vent variable. Terrestrial or marine. 



Obs. The animals of this family are known in popular language under the name of Slugs, 

 or Slug-worms. They inhabit moist places, and move by successive contractions of the 

 muscular fibres of the foot, leaving a shining trace in their path. Feed on vegetables, and 

 are very voracious. They are mischievous in the gardens in some parts of Europe ; but 

 owing probably to the lesser humidity of our climate, their numbers, and consequently their 

 injurious effects are comparatively trifling here. 



The Limaces of the United States have, until recently, been little studied. Mr. Binney is 

 the only American naturalist who has investigated the subject to any extent, and his nomen- 

 clature will for the most part be adopted in this family. 



GENUS LIMAX. Linneus. Lamarck. 



Animal with its body more or less elongated, semicylindrical, tapering to a point. Mantle 

 partial, and placed on the anterior portion of the body, wrinkled. Head tolerably distinct, 

 retractile. Four retractile tentacles ; the upper pair longest, and bearing the eyes. Foot 

 occupying the lower part of the body, without processes, and scarcely distinct from the 

 rest of the body. Breathing-hole and vent on the right side of the body. Generative ori- 

 fice between or near the upper tentacles. 



LiMAX AGRESTIS. 



PLATE I. FIG. 4. — ;(STATE COLLECTION.) 



L.agrestis. LiNN. Lam. An. sans vert. Ed. 2, Vol. 3, p. 264. 



li. tanicata. GouLD, Invertebrala of Mass. p. 3. 



X. agrestis. Binney, Desc, Limacidx, Bost. Journ. Nat. Hist. Vol. 4. 



Description. Body with numerous minute longitudinal interrupted wrinkles, and a distinct 

 ridge extending from between the upper pair of tentacles to the mantle, with a furrow on each 

 side. Foot narrow, with two distinct longitudinal furrows on each side. Tail somewhat 

 acute. Mantle contains within the rudiment of a delicate oval shell. Tiie mantle is elliptical 

 or oblong-oval, much elevated, convex, and, in a state of repose, covers nearly one-half of the 

 body ; when in motion, scarcely equals one-third of the length of the body : its surface with 



