CHONDBIN^E OF THE ALPIC CENTER. 17 



weakly arcuate margins; lamellae and plicae 9: 3 parietal, 2 

 columellar, 4 palatal, none of them reaching the peristome, 

 the upper one very small; margin whitish, somewhat ex- 

 panded below and on the left. Length 7%-9%, diam. 2%-3% 

 mm. Lake Garda, Tirol. (P. avenacea transiens ad mega- 

 cheilos Strobel. P. megacheilos var. avenoides and var. bigor- 

 riensis Westerlund, Fauna Europaea Moll, extramar. Prodr., 

 ii, 1878, p. 168. P. avenacea var. transiens West., Fauna, iii, 

 1887, p. 98. Var. transiens W., Caziot, Ann. Soc. Linn. Lyon, 

 1908, p. 165.) Differs from megacheilos by having the last 

 whorl rounded at the base, the base of the aperture regularly 

 rounded, the lip not reflected and the more deeply placed 

 palatal plicae (West.). This appears to be a well-marked sub- 

 species, which should evidently bear the earliest name, C. ave- 

 nacea avenoides West. See also Gredler, Nachrbl., 1878, pp. 

 20, 21. 



Var. megacheUoides Clessin. Shell moderately umbilicate, 

 ovate-conic, usually of lighter color; peristome somewhat 

 lipped; aperture with 3 nearly equal palatal plicae standing 

 directly opposite the columellar folds and the inner fold of the 

 parietal wall, and one small upper palatal plica far within. 

 Neck obtuse on the margins, usually without furrows. South- 

 ern Tirol, Doss Trento and S. Bernardino near Trient, Segno 

 in the Nonsberge, etc. (Pupa avena Drap. Gredler, Conch, aus 

 den Nordosten Tirols, 1860, p. 104. Torquilla avenacea var. 

 megacheUoides Clessin, Molluskenfauna Oesterreich-Ungarns 

 u. der Schweiz, 1887, p. 229). Probably a synonym of var. 

 avenoides West. 



Var. transiens Clessin. Shell as in the preceding variety, 

 but more slender, regularly striate, darker colored ; peristome 

 less lipped. South Tirol, Bozen on porphyritic rocks, on the 

 Schloss Rungelstein, near Dolsach in the Drauthal, on primi- 

 tive rocks (the first fold rudimentary). (Pupa avena Gred- 

 ler, Tirol, p. 104. Torquilla avenacea var. transiens Cless., 

 Moll.-fauna Oesterreich-Ungarns, 1887, p. 229.) This is not 

 transiens West., which probably has priority. 



Var. gredleriana Clessin. Shell somewhat smaller; neck 

 compressed, keel-like, the upper palatal fold wanting or rudi- 



