HELIX 



1T9 



number and arrangement of the ribs is not constant ; a fact 

 noticed in other species. 



Fig. 313. 



Jaws of Belix tryoni. 



The lingual membrane has 190 rows of 43 — 1 — 43 teeth each ; 

 centrals and first nine laterals obtusely conical ; last seven laterals 



Fig. 314. 



Lingual dentition of Helix tryoni. 



and first five uncini of same shape, but with obtuse side cusp ; 

 balance of uncini serrated. 



Helix pandorae, Forbe.s.— Shell imperforate, globose-couic, rather 

 solid, reddish above, violet on the apex, ashy below, bound with nuinerons, 

 interrupted, light blotches and lines ; whirls five, rounded ; suture im- 



