THE NATURAL HISTORY SURVEY. 193 



dirty white, blackish or bluish on head, tentacles and eye- 

 peduncles; pedal grooves and mucus pore as in ligera. 



Jaw: Similar to that of ligera. 



Radula formula: y + ^5 '+4-^ + 8,9 ( 45 _!_ 45 ) ; charac- 

 ters of the teeth not differing essentially from those of ligera. 



Genitalia: Differing from ligera in having a second acces- 

 sory pyriform gland to the dart sac. (Binney.) 



Distribution: Western Pennsylvania to Georgia, west to 

 Arkansas and eastern Texas. (Pilsbry.) 



Geological distribution: Pleistocene; Loess. 



Habitat: Same as that of ligera. 



Remarks: Distinguished from ligera by its smaller size, 

 more depressed spire and transverse aperture. This is not a 

 common species and seems to be confined to the southern 

 region, as no specimens have thus far been collected in any 

 other part of the territory. 



FAMILY 



"Shell rudimentary, a calcareous plate, not spiral, concealed 

 under the mantle, and covering the respiratory cavity. Foot 

 with or without mucus pore; jaw oxygnathous, arcuated, with- 

 out ribs, with a rostriform projection on the inferior margin; 

 lingual plate with a tricuspidate central tooth, the middle cusp 

 long and narrow, laterals bi- or tricuspidate, marginals narrow, 

 sharp, uni- or bicuspidate." (Tryon.)* 



GENUS LIMAX Linne, 1758. 



"Animal attached its whole length to the foot, subcylin- 

 drical, tapering behind, bluntly truncate anteriorly; tentacles 

 simple; mantle small, anterior, enclosing a shelly plate; no 

 caudal mucus pore; a distinct locomotive disk; external anal 

 and respiratory orifices at the right posterior margin of the 

 mantle; orifice of combined generative organs behind and be- 

 low the right peduncle." 



"Shell-plate testaceous, thin, flat, longer than wide, with 

 concentric striae of increase, internal." 



"Jaw smooth with median projection. Lingual membrane 

 long and narrow; central teeth tricuspid, laterals bicuspid, mar- 

 ginals aculeate, often bifid. Considerable variation is found in 

 the dentition of the genus; the centrals and laterals are some- 

 times unicuspid." (Tryon.)* 



*Struct. and Syst. Conch., Vol. Ill, p. 78- 



