208 EUROPEAN SPECIES OF VERTIGO. 



The first description of this snail, so far as I can learn, was 

 that of Sandberger in 1875; from this it appears that the 

 form with a weak parietal tooth as well as one opposite it in 

 the palate [lower palatal], is to be regarded as typical. It is 

 that which he figures. Boettger states that according to his 

 understanding typical parcedentata forms have 1 or 2 blunt 

 denticles, and occur in his environs in the younger Middle- 

 Pleistocene loess of the ' ' Erbenheinier Talchens bei Wiesbaden 

 und von Schiersteiu und im alten alluvium des Grossen Bmchs 

 bei Traisa in der Prov. Starkenburg. ' ' Outside of this region 

 it is known from the loesses of Heidiugsfeld, Wiirzburg and 

 Regensburg, and the toothless form has also been recognized 

 in England and Scotland, perhaps also in France. 



According to Boettger, the earliest Pleistocene forms known 

 appear to have been toothless; afterward variable, partly 

 toothed forms in the later Pleistocene and Alluvium, finally 

 extinction of the toothed parcedentata stock, which Boettger 

 considered to belong to lower elevations, the toothless genesii 

 alone surviving, and only in Alpine and high northern regions. 



In his paper of 1887 Sandberger described the following 

 varieties, the first three probably referable to I 7 , alpestris. 



Var. quadridens (pi. 18, fig. 14). Aperture armed with one 

 mammilliform parietal tooth, one columellar and two on the 

 throat [palate], of which the anterior is smaller. 



Var. tridens (pi. 18, fig. 13). Anterior tooth of the throat 

 obsolete or wanting, the rest present. 



Var. adversiden-s (pi. 18, fig. 16). No columellar tooth, the 

 rest are apparent. 



Var. Widens (pi. 18, fig. 15). Columellar and anterior 

 tooth of the throat wanting. This form is the typical 

 parcedentata. 



Var. glandicula (pi. 18, fig. 19). Only the parietal tooth 

 visible. 



Var. genesii (pi. 18, figs. 10-12). Toothless; bright brown 

 in life, subpellucid, the margins of aperture violacous-brown 

 [= genesii Gredler] . 



Dr. Boettger considers the relatively large, 4-toothed loess 

 form which Saudberger described as var. quadridens to be 



