270 DR JOHNSTON'S DESCRIPTIVE CATALOGUE OF THE 



Penn. Brit. Zool. iv. 299. tab. 89. fig. 7. Cingula Ulvso, Flem. 

 Brit. Anim. 308. Paludina Ulva?, Forbes, Faun. Mon. 18. 



Hab. Muddy inlets. Shore below Beal, browsing on the Salicornia. Holy 

 Island. Near Warren Mill. 



The lip is often reflected on the pillar as in some Rissose. Snail blackish ; 

 mouth proboscidiform, slightly bilobed ; tentacula tapered with a dark 

 ring at the tips, the eyes near the thickened base and external ; foot 

 rather short, rounded behind, truncate in front ; pale with a yellowish 

 tint, the margins plane. Can float at the surface in a reversed position. 



12. LACUNA. TURTON. 



Shell conoid or somewhat globular, thin ; aperture roundish or oval, 

 with the lips disjoined ; pillar flattened, with a longitudinal groove ter- 

 minating at the upper end in an umbilicus : operculum horny, thin. 



1, L. pallidula, shell subglobular, ventricose, thin, subpellucid, yel- 

 lowish horn colour ; whorls four, the spire depressed with minute 

 but well-defined whorls ; aperture wide, lunate, the pillar white, 

 and the umbilicus large. Diam. T 4 s ths. Turton in Zool. Journ. 

 iii. 190. Nerita pallidula, Dillw. Rec. Sh. 986. 



Hab. Berwick Bay, on the leaves of Fuci near low- water mark, frequent. ^ 

 Animal yellowish, unspotted : tentacula two, setaceous, the eyes at their 

 outer base, small, prominent : mouth shortly proboscidiform : foot oval, 

 obtuse posteriorly, plain : operculum horny, lunate, spiral at the base. 



2. L. vincta, shell ovato-conical, subpellucid, smooth, with six round- 

 ed whorls, the lower faintly striated and marked with four brown 

 bands, two of which are continued up the spire ; aperture subor- 

 bicular, the pillar rounded, with a narrow groove and perforation. 

 Length f^ths, breadth ^ths. Turton in Zool. Journ. iii. 192. 

 Turbo vinctus, Mont. Test. Brit. 307, tab. 29. fig. 3. 



Hab. On the leaves of Fuci about low-water mark, common. 



The following varieties have occurred in our bay : 



(a) Shell thickish, the spire depressed, the body with only two narrow dis- 

 tant bands. 



(6) Shell with the spire depressed, and three bands of a pine red colour on 

 the body, the middle one broad. These two varieties belong to the L. 

 quadrifasciata of Turton, or Turbo quadrifasciatus of Montagu, Test Brit. 

 328, tab. 20, fig. 7- 



<o) Shell of a very pale rose colour without bands. 

 (d) Shell of a uniform yellowish-horn colour. 



In all the body-whorl is obscurely angulated near the foase, and at the suture, 

 which is made more obvious by a whitish band winding up the spire. 

 The snail is of a pale flesh colour, the proboscidiform mouth reddish- 

 orange, the sides, and sometimes the head, dusky or black : tentacula 

 setaceous, contractile, the eyes on short pedicles at their base : foot oval, 

 rounded at both ends, widest behind, the anterior end capable of being 

 extended considerably beyond the head, the margins plain, but there are 

 two very short filaments between the hinder part and operculum. It 

 swims on the surface in a reversed position, and it frequently leaves the 

 water to settle on the surface of fuci exposed to the atmosphere. 



