270 DR Johnston's descriptive catalogue or the 



Petm. Brit. Zool. iv. 299, tab. 89, fig. 7. Cingula Ulvse, Flem. 

 Brit. Anim. 308. Paludina UlviB, Forbes, Faun. Mon. 18. 



Mab. Muddy inlets. Shore below Beal, bi-owsing on the Salicoruia. Holy 

 Island. Kear Warren Mill. 



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

 month 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 ; jDale with a yellowish tint, 

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



12. Lacuna. Tueton. 



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

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

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



1. L. jmllidula, shell subglobular, ventricose, thin, subpellucid, 

 yellowish horn colour ; whorls four, the sjiire depressed with 

 minute but well-defined whorls ; ajjerture wide, lunate, the pillar 

 white, and the umbilicus large. Diam. vVths. Turton in Zool. 

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



Hah. 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, spii'al at the base. 



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

 rounded whorls, the lower faintly striated and marked with four 

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

 suborbicular, the pillar rounded, with a narrow groove and per- 

 foration. Length -A-ths, breadth vVths. Turton in Zool. Journ. 

 iii. 192. Turbo vinctus, Mont. Test. Brit. 307, tab. 29. fig. 3. 



Hah. 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 distant 

 bands. 



(b) Shell with the spire dei^ressed, 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 quadrifasciatns of Montagu, Test. Brit. 

 328, tab. 20, fig. 7. 



(c) 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 base, and at the suture, 

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

 snail is of a ijale flesh colour, the proboscidiform mouth reddish-orange, 

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

 contractile, the eyes on short ])edicles at their base : foot oval, rounded at 

 both ends, widest behind, the anterior end ca])able of being extended con- 

 siderably 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 sui-face of fuci exposed to the atmosphere. 



