360 BULLETIN OF THE 



respiratory orifice!? at the riglit posterior margin of the mantle: orifice of com- 

 bined generative organs behind and below the right eye-peduncle. 



Shell-plate testaceous, thin, flat, longer than wide, with concentric strife of 

 increase, internal. 



Jaw smooth, with median projection. 



Lingual membrane long and narrow : central teeth tricuspid, laterals bicuspid, 

 marginals aculeate, often bifid. Considerable variation is found in the denti- 

 tion of the genus ; the centrals and laterals are sometimes unicuspid. 



Universally distributed. 



For figures of animal, shelly plate, jaw, and lingual dentition, see Terr. Moll. 

 U. S., V. 



The following generic and subgeneric names have been suggested for species 

 of Limax, founded mostly on peculiarities of the mantle, genitalia, and lingual 

 dentition : EuUmax, Agriolimax, Milax, Amalia, Lehmannia, Limacus, Kry- 

 nickellus, Krynickia, Heyne^nannia, Plecticolhnax, Hijdrolimax, Lallemannia, 

 Malino, Malinaslrum, Gestroa, ChromoUmax, Opilolimax, Stabilea, Malkolimax, 

 Megapelta, Clytropelta, Ibycus. 



Parmacella, Cuv. {Cryptella, Webb & Berth., Girasia, Drusia, Gray, part.) 

 Animal limaciform, subcylindrical, swollen behind, gradually attenuated be- 

 fore : tentacles simple : mantle large, central, concealing the shell : no longi- 

 tudinal furrows above the margin of the foot, and no caudal mucus pore : 

 distinct locomotive disk ? external respiratory and anal orifices at the right 

 posterior margin of the mantle : orifice of combined generative organs behind 

 and below the right eye-peduncle. 



Shell small, testaceous, internal, rudimentary, subspiral, aperture very large, 

 dilated anteriorly. 



Jaw smooth, with a median projection. 



Lingual membrane with tricuspid centraLs, first laterals tricuspid also, mar- 

 ginals aculeate. 



Around the Mediterranean, Canaries, Central Asia. 



For figure of animal and jaw see Moquin-Tandon, Moll. Terr, et Fluv. de la 

 France. For description of lingual dentition, see Semper, Phila. Arch., 89. 



The young animal is entirely enclosed in the shell, which is furnished with 

 a .sort of operculum. As the animal grows, the operculum falls, the shell be- 

 comes covered with the mantle, and only increases at its outer margin like the 

 simple shell-plate of Limax. 



Tennentia, IIumb. Body limaciform, subcylindrical, attenuated behind : 

 tentacles simple : mantle large, anterior, concealing the shell : longitudinal fur- 

 rows above the margin of the foot, meeting over a linear caudal mucus pore : 

 distinct locomotive disk : external respiratory and anal orifices on the right 

 central margin of mantle : orifice of combined genital system behind and below 

 the right eye-peduncle. 



Shell internal, small, rudimentary, convex above, flat below, apex on right 

 posterior side, recurved. 



