3S Classifications of North American Helices. 



coarctata ; perist. albo-labiatum, expanso-reflexum, margine basali rare 

 unidentato. 



Maxilla costis crassis circa 10, valde proininentibus. 



20. Acantiiinula Beck. 



T. perforata, globoso-turbinata, vel epidermide brunnea, costulato- 

 plicata vol aculeata induta; anfr. 4-5; apertura rotundata ; perist. 

 tenue, expansiusculura, marginibus approximates. 



Tentacula inferiora et palpi labiales sat magna. (Moquin Tandon.) 



2!. Vallonia Iiisso. 



T. umbilicata, depressula, diaphana; anfr. 3A-4 ; apertura obliqua, 

 subcircularis ; perist. candidum, labiatura, reflexum, marginibus conti- 

 guis vel conniventibus. 



Maxilla costis unmerosis, margine par urn crenulato. Folliculi mucosi 

 nulli ? Sagitta 1, longa, conica, Isevis. (Goldmss.) 



23. Fruticicola Held. 



T. umbilicata vel perforata, depresso-globosa, interdum pilosa ; anfr. 

 5-1 convexiusculi ; apertura late lunaris vel lunato -rotund a; perist. acu- 

 tum, brevissime expansum, intus labiatum, margine basali reflexo. 



Maxilla costis uumerosis (usque 20), margine subtiliter crenulato. 

 Folliculi mucosi pleruraque 2, bi-quinquefidi. Sagitta 1—2, conica, arcu- 

 ata, apicem versus aciebus instructa. Vesicula pedunculata magna, 

 appendice coeca carens. (Paascb.) 



37. Arionta Leacb. 



T. umbilicato-perforata, conoideo- vel depresso-globosa, tenuis; anfr. 

 5-6, ultimus leniter descendens; apertura Junato-rotunda ; perist. late 

 labiatum, marginibus parallels, basali dilatato, umbilicum saepe tegente. 



Maxillis costis 4-6, distantibus, prominentibus, ina3qualibus, margine 

 dentato. Folliculi mucosi 2, simplices. Sagitta 1 arcuata, apice incras- 

 sata, basi biangulata. 



52. Polymita Beck. 



T. aperte vel obtecte perforata, globosa, nitida, spira brevis; anfr. 4-5, 

 ultimus magnus, ad aperturam detlexus ; columella basi dilatata ; aper- 

 tura contracta, subverticalis, rotundato-lunaris ; perist. simplex, obtusum, 

 intus labiatum, marginibus distantibus.' 



