Physa alba, Bulimus tuber culatus, ^S 



ribs, without intermediate smaller ones ; in the greater angularity 

 of the anterior cardinal margin ; in the wide gape on both sides; 

 dnd in the strong internal rib round the anterior opening: and 

 from L. bullata of Sowerby, in the obliquity of the hinge. 



We dredged up half a dozen living specimens, of various sizes, 

 in the British Channel. They had no byssus attached to them, 

 nor has the L. Loscomhi, when taken alive. 



Icon. tab. xiii. fig. 2. 



Mus. nost. 



3. Physa alba. 



Testa sinistrorsa, ovata, ventricosa, albo'Cornea^ pellucidii / aw- 

 fractibus quatuor, tumidis, eccsertis : aperturd ovaid» 



Shell sinistral, oval, ventricose, white horn-colour, transparent ; 

 volutions four, tumid and produced. 



Length four tenths of an inch ; breadth about three tenths. 



This very distinct species is found in the river Towin, in North 

 Wales. In the tumidity of the volutions and the obliquity of the 

 sutures, as well as in its colour, it differs from any species yet 

 described. The Ph. rivalis is oblong, of a yellow horn-colour, 

 with the volutions very little raised or swollen, and the aperture 

 is oblong. In fig. 2. tab. 4. of the 8th Vol. of the Linnean Trans- 

 actions, Ph. rivalis is erroneously represented as a dextral shell. 



Icon, tab, xiii. fig. 3. 

 . Mus. nost. Blomer. 



4. Bulimus tuberculatus. 



Testa ovattt'oblonga, albido~fusca, basi lactcci subumbilicata: peri" 

 tremate lacteo, subrejlexo : aperturd siiperne uni-iuberculatd. 



Shell oval-oblong, whitish-brown, white and somewhat umbi- 

 licate at the base : margin of the aperture white and slightly re- 

 flected, with a single tubercle at the upper and outer angle. 



Length half an inch; breadth three-tenths. 



A very beautiful species, in size between the B. montanus and 

 B, obscuriis, found at Pershore in Worcestershire. In colour it 

 varies from milk-white to brownish-white, but the lower half of 



