33° 



The Irish Naturalist. 



November, 



cellaria, though under certain physiological circumstances the 

 spermatheca of cellaria itself assumes a somewhat similar 

 shape. Its duct, in V. hibernica, is longer : the vagina is 

 relatively long and twisted. The penis and epiphallus are 

 large and distinct, so also is the dilatation of the vas deferens. 

 On the whole, one may say that these organs are more .sugges- 

 tive of V. lucida than of V* cella?ia. Throughout the. group 

 there is of course great variation due only to the physiological 

 age and condition of the individual. The abortive develop- 

 ment sometimes found in undoubtedly adult V. cellaria may 

 probably be correlated with the parthenogenetic habit which 



Scale of Millimetres 



Fig. i. Radulae of Vitrese in situ. 

 A. V. hibernica, Kenn. B. V. cellaria, Miill. 



Scale of Millimetres. 



Fig. 2. Genitalia of 

 V. hibernica, Kenn. sp n. 



[ach diviS.0K= 10 mi( ra 



'■ ■ •■ ' • '■ '. • • ; 



Fig. 3. Radular Teeth of Vitreoe. 

 A. V. hiberm'ca, Kenn. sp. nov. B. V. cellaria, Miill. 



is recorded of that species. L,ike many other ill-bred 

 creatures, V* cellaria is amazingly prolific, and apparently it 

 not unfrequently omits to go through a part of the normal 

 process. 



