364 



ally furnifhed with three white teeth, two on the Colu- 

 mella, and one on the exterior lip oppofite ; and a large 

 plate, or protuberance, at the angle of the outer lip. 

 Length half a line, or fcarce larger than a poppy feed. 



It has much the habit of Turbo fexdentatus, but be- 

 fides its being reverfed, it is more cylindric, more ob- 

 tufe at the apex, and differs effentially in the fliape of 

 the aperture, and in the teeth. 



We were firfl favoured with fpecimens of this fpecies 

 by Mr. Boys of Sandzvich, who informed us, it was not 

 uncommon at that place, on old walls covered with ivy: 

 and have fince found it rarely amongft the rejedamenta. 

 of the river Avon in Wiltjliire. 



The infant ftate of this (liell has much the appear- 

 ance of a Trochus, the aperture is quadrangular, tranf- 

 verfely comprefied; and the bafe flat and umbilicated. 



MuLLER gives this fliell fingly, in his twenty-fourth 

 genus, under the title of Vertigo : the charafters being 

 taken from the animal, run thus, *' Tentaculis duobus 

 '^linearibus, apice oculatis" 



This is, we believe, the only inflanceof a Ivnax pof- 

 feffing but two tentacula, furniflied with eyes at their 

 dps, and none at their bafe. 



With 



