305 



apex rather pointed: aperture fub-orbicular ; inner lip 

 thick, a little reflefted, and fometimes in old (hells forms 

 a fmall depreflion, or fub-umbUiciis : colour dirty yel- 

 low-white, or brown. Length three-quarters of an inch ; 

 breadth rather lefs. 



■ 



Very young fliells are of a deep-brown colour, but in 

 every other refpcft the fame ; except being proportion- 

 ably more flender. 



This fpecies, which no doubt has been confounded 

 with T. littoreus, is at once difcriminated by the round 

 tumid volutions, in all its various Ilages of growth. It 

 is not fo common as that fliell, but is found plentiful on 

 the fhores about Falmouth, efpecially under Pendennis 

 Caftle, adhering to the rocks. We have alfo found it at 

 Plymouth, and other parts of the Devonjhirc coalt ; bur 

 rarely above half an inch in length. 



Animal yellowifli, without fpots or ftripes, with two 

 fetaceous tentacula of the fame colour, mofl commonly 

 marked with a longitudinal dufky flreak on the outfide. 



The invariable difference in the colour of the animals 

 of this and the littoreus, is a ftrong charafteriftic diflinfti- 

 on. In the oi)erruluvi they alfo differ ; this is more round 

 and more ftrongly fpirally ftriated ; but both are equally 

 corneous, and permanent. 



We have lately been favoured with fome notes taken 



R r by 



