GASTEROPODA. 167 



FAMILY II. LiMACTDiE. Slugs, 



Shell small or rudimentary, usually iuternal, or partly concealed by the 

 mantle, and placed over the respiratory cavity. 



Animal elongated ; body not distinct from the foot ; head and tentacles 

 retractile ; tentacles 4, cylindrical, the upper pair supporting eyes ; mantle 

 small, shieldshaped ; respiratory and excretory orifices on the right side. 



Fig. 92. Limax Sowerbii Fdr, Brit. 

 LiMAX, L. Slug. 



Type, L. maximus. PL XII. fig. 25. (L. cinereus, Miill.) 



Shell internal, oblong, flat, or slightly concave beneath, nucleus posterior ; 

 margin membranous ; epidermis distinct. 



Aniynal, foot pointed and keeled behind; mantle shieldshaped, on the 

 front of the back, granulated or marked with concentric strise ; respiratory 

 orifice on the right side, near the posterior margin of the mantle ; repro- 

 ductive orifice near the base of the right ocular tentacle; lingual teeth 

 tricuspid, those near the margin simple, aculeate. 



The slugs are connected with the snails by Fitrina ; their teeth are 

 similar, but have more elongated cusps. The creeping-disk, or sole of the 

 foot, extends the whole length of the animal ; but they frequently lift up their 

 heads, like the snails, and move their tentacles in search of objects above 

 them. They often climb trees, and some can lower themselves to the ground 

 by a mucous thread. When alarmed they withdraw their heads beneath the 

 mantle, as in fig, 92. Slugs feed chiefly on decaying vegetable and animal 

 substances ; they oviposit at any time of the spring and summer when the 

 weather is moist, and bury themselves in drought and frost. Limax nodi- 

 lums, Fer. (Phosphorax, Webb.) found in Tenerifi'e, has a luminous pore in 

 the posterior border of the mantle. 



Distr. 22 sp. Em'ope, Canaries, Sandwich Ids. 



Fossil. Eocene — . Brit. The Ancylus ? latus, Edw. of the I. Wight 

 appears to be a Limax. 



Suh-genus. Geomalacus {maculosus) Allman. Ireland. Shell ungui- 

 form. Animal with a mucus gland at the extremity of the tail ; respiratory 

 orifice near the right anterior border of the mantle. 

 Incilaria, Benson. 



Type, I. bilineata. Cantor, Chusan. Syn. ? Meghimatium, Hasselt. 



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