44 CHONDRINJE OP THE PYRENEAN CENTER. 



Differs from letoumeu&i, according to Bourguignat, by the 

 conoid form, more glossy shell of a lighter tint, by the more 

 separated, blunter, much less strong costulations, by the ab- 

 sense of a median furrow on the last whorl, as in letourneuxi; 

 by the outer margin not angular and not projecting forward 

 by the less projectng columellar folds, not obliquely entering ; 

 by the upper palatal plica not converging to the parietal fold, 

 and by the plications of the parietal callous, which have a 

 lamelliform, not a punctiform appearance as in letourneuxi. 



Section MODICELLA Ads. 



Series of C. farinesii. 



These forms of the Pyrenees and southeastern Spain differ 

 from avenacea by the weakness or loss of teeth; of palatal 

 folds there are not more than two, often one or none. Parietal 

 and columellar margins each bear two, one or no lamellae. 

 When present, the lamellae and folds are small and short. 



As is usual in series showing degeneration of the teeth, the 

 individual lamellae and plicae become highly variable, and their 

 value as specific characters is correspondingly diminished. 



There has been no rational revision of the many local forms, 

 races or species. The work can be done only by a naturalist 

 able to get a practical knowledge of them in the field and by 

 study of the types or topotypes. 



As the data are not at hand for construction of a key, some 

 of the more obvious characters have been tabulated below as 

 an aid in determination. In the second column of the table, 

 a indicates the presence of an angular lamella. 



