84 ARIONID^. 



mucous pore ; a distinct'locomotive disk ; exterior respiratory and 

 anal orifices on the anterior right margin of the mantle ; orifice 

 of the combined genital sj'stem below the last. 



Internal calcareous grains, in some species agglomerated, 

 forming an imperfect shell-plate. 



Jaw ribbed. Lingual membrane with tricuspid central teeth, 

 tricuspid or bicuspid laterals, and quadrate marginals. 



The " land-soles " occasionally devour animal substances, such 

 as dead worms or injured individuals of their own species. They 

 lay "T 0-1 00 eggs between May and September, are 26-40 days 

 hatching, and attain their full growth in a year; they begin to 

 oviposit a month or two before that period. The eggs of A. 

 hortensis are very phosphorescent for the first fifteen days 

 (Bouchard). 



BAUDONiA, Mabille. Distinguished from Arion by being 

 anteriorly enlarged and depressed, the shield almost smooth, 

 the head well separated from the body, and the tentacles rather 

 small. Characters of but little value. 2 Portuguese sp. 



ARiUNCULUS, Lessona, 1881. Genital orifice nearer the tentacle 

 than the pulmonary orifice. 3 sp. A. Spezias, Lessona. Pied- 

 mont. 



LOCHEA, Moquin-Tandon, 1855. Shell represented by unequal, 

 isolated, calcareous granulations. A. rufiin, Linn. Europe. 



PROLEPis, Moquin-Tandon, 1855. Shell rugose, produced hy 

 the aggregation of separate calcareous particles. A. fuscua, 

 Miill. Europe. 



Arioltmax, Morch, 1860. 



Distr. — 5 sp. Pacific coast of United States. A. Golumhianus^ 

 Gould (ci, 54). 



Animal limaciform, subcjdindrical, tapering behind ; tentacles 

 simple ; mantle anterior, small, concealing an internal shell- 

 plate ; longitudinal furrows above the margin of the foot, 

 meeting over a caudal mucous pore ; a distinct locomotive disk ; 

 external respiratory and anal orifices on the posterior right 

 margin of the mantle ; orifice of combined genital S3'stem on the 

 right side of the body, below the anterior free edge of the mantle. 

 Shell-plate internal, solid, flat, longer than wide. 



Jaw ribbed. Lingual membrane with tricuspid centrals, 

 bicuspid laterals and quadrate marginals. 



Ariolimax differs from Prophysaon by the position of the 

 respiratory orifice in the hinder half, and of the genital orifice 

 below the free part of the shield, and the presence of a mucous 

 pore. 



Geomalacus, Allman, 1843. 

 Distr. — Eastern Europe. G. maculatus, Allm. (ci, 55). 

 Animal limaciform, subc^dindrical, blunt behind; tentacles 



