256 



HELICIDJE. 



exterior rib, which is of the same colour as the rest of the 

 shell and situate near the opening of the mouth ; outer edge 

 consider ably inflected : inner lip scarcely perceptible and con- 

 sisting of a mere film : umbilicus rather open. L. O08. B. 0-06. 



Var. bidentata. Labial or palatal teeth wanting. 



HABITAT : Under stones by the side of a small lake 

 at Ballinahinch near Roundstone, Co. Galway, where I 

 made this acquisition to the British Mollusca in 1845. 

 V. antivertigo and a variety of V. pygmcea were also 

 found by me at the same place and time ; but I had not 

 examined my specimens until I commenced describing 

 the species of Vertigo for this work. The mouth and 

 lip in the variety are completely formed. On the Con- 

 tinent the present species occurs in the North, South, 

 and West of France, the Cantons of Vaud and Valais in 

 Switzerland, and near Heidelberg. It is a local and rare 

 shell. 



The description of the animal is taken from my " Notes 

 on Swiss Mollusca," which appeared in the ' Annals and 

 Magazine of Natural History ' for January 1855 ; and I 

 there stated that the body is more slender and of a lighter 

 colour than that of V. antivertigo, and that the ten- 

 tacles are more decidedly clavate. There is no trace of 

 a second or lower pair of tentacles. I observed it in 

 Switzerland feeding on Conferva. The situations in 

 which I found it in Switzerland were like that of the 

 Irish habitat ; and I have no doubt that it will be re- 

 discovered in this country by attention being thus drawn 

 to it. The fen districts of our Eastern counties, as well 

 as the wilds of Connemara, require to be more thoroughly 

 searched. I did not keep one of my Swiss specimens, 

 from a desire to confine my collection exclusively to our 

 own Mollusca ; but I have fortunately had, through the 

 kindness of Mr. Daniel, an opportunity of comparing 



