CHONDRIN^E OF THE ALPIC CENTER. 7 



arrangement has its flaws, and the number of subordinate 

 groups into which the three main series or sections may be 

 split is here, as everywhere, purely a matter of convenience. 

 The presence of several series of independent origin, in which 

 the teeth have been reduced or lost, adds to the complexity of 

 specific classification. 



Sections of Chondrina. 



a. 1 Shell brown, of different shades. 



b. 1 Lamellae and plicae well developed, 6 or more. Sec- 

 tion Chondrina, p. 7. 



c 1 . Alpic; series of C. avena-cea, no. 1 to 8. 

 c 2 . Pyrenean ; series of C. bigorriensis, no. 9 to 28. 

 &. 2 Teeth small or wanting; not more than 2 plicee in 

 the outer-basal lip. 



c 1 . Pyrenees and Spain. Section Modicclla, p. 44. 

 c 2 . Alpes Maritimes and Liguria, species no. 3, 4. 

 a-. Shell opaque, whitish or very pale. Southern France and 

 Italy. Section Solatopupa, p. 57. 



It should be noted that some species of the avenacea group 

 and of Solatopupa have degenerate teeth, as in the section 

 Modicella. See species no. 3, 4, 42, 43. 



Section CHONDRINA s. str. 



Series of C. avenacea. 



1. CHONDRINA MEGACHEILOS (Cr. et Jan). PI. 1, figs. 1, 2, 3. 

 The shell is more or less openly umbilicate, nearly smooth 

 or somewhat wrinkled, chestnut-brown to chocolate, paler 

 above, shining. Spire slowly tapering, the penult whorl nearly 

 as wide as the last ; latter part of last whorl compressed into 

 a narrow ridge below, flattened laterally, and often weakly 

 impressed over the upper and lower palatal plicae. Aperture 

 oval, armed with 9 teeth : angular lamella long, continuous, or 

 almost joining the short, higher, spiral lamella; parietal 

 lamella short. Columellar lamella is strong and rather long, 

 not quite reaching the peristome ; subcolumellar smaller, 

 shorter. Five palatals, the sutural and suprapalatal plica? 



