CHONDRIN^ OF THE ALPIC CENTER. 



Doubtless all records from the Pyrenees, from those of 

 Boubee and Des Moulins on, pertain to other species. It is 

 not found in southern France beyond the dep. Alpes-Mari- 

 times and Alpes-Basses, and even there the colonies are ap- 

 parently few and small. According to Adami, the large, 

 typical forms are at elevations above 2000 meters, smaller 

 forms being found at lower levels. 



Commandant Caziot regards the bigorriensis group of the 

 Pyrenees as modifications of a megacheilos stock which radi- 

 ated from the Alpic center, but I am disposed to look upon the 

 bigorriensis group and megacheilos as parallel mountain modi- 

 fications of an early avenacea-\ike stock, and not otherwise 

 directly related. 



Jan's original description is as follows: Chondrus mega- 

 cheilos. Ch. with the shell dextral, conic-cylindric, the sum- 

 mit a little obtuse (alt. 4y 2 , width iy 2 lines). Aperture 7- 

 plicate (alt. 1%, width 1 line) peristome wide, white. North- 

 ern Italy. 



Torquilla tricolor Villa was said to differ from megacheilos 

 by the greater size, thicker shell, more reflected peristome and 

 more numerous apertural folds (8) ; length 11-13, diam. 5 mm. 

 In humid, limestone mountains of Valsassina, province of 

 Como. This name may be used for the large form of mega- 

 cheilos if one is needed. 



Form minor West. Length 5 1 / 2 -6, diam. 2 mm. Different 

 from avenacea. by the compressed, keeled base of the last whorl, 

 reflected lip, the mouth angular below, the straightened colu- 

 mellar lip, etc. (Fauna, iii, 1887, p. 96). No locality was 

 given by Westerlund, but Schroder has reported it from near 

 Gargnano, Salo, etc., on Lake Garda (Nbl., 1913, p. 174). 

 Caziot also figured a "var. minor" from north of Grasse, 

 length about 5.7 mm. 



Var. toscolana Schroder. Shell similar to the type except 

 that it is stronger ; whorls 8-9 ; throat set with many folds and 

 tooth-like tubercles (up to 16 !). Length ll-14i/ 2 , breadth 4-5 

 mm. On cliffs in Toskolano valley, in the mountains west of 

 Lake Garda (Modicella megacheilos Jan, var. toscolana, Schro- 

 der, Nachrbl. d. m. Ges., vol. 45, 1913, p. 174). 



