SKENEA. 157 



Helix depressa, MoNT. Test. Brit. p. 439, pi. 13, f. 5. 



Turbo depressus, Maton and Rack. Trans. Linn. Soc. vol. viii. p. 170. — Turt. 



Conch. Diction, p. •228. — Dillw. Recent Shells, vol. ii. 



p. 883.— Wood, Index Testaceol. pi. 32, f. 164. 

 Skenea dfipressa, Fleming, Brit. Animals, p. 313. — Forbes, Malac. Monens. 



p. 19, animal. — Johnston, Berwick. Club, vol. i. p. 273. 



— Macg. Moll. Aberd. p. 134, — Brit. Marine Conch. 



p. 158. 

 Delpldnoidea depressa. Brown, Illust. Conch. G. B. p. 20, pi. 8, f. 35, 36. 



Of a depressed orbicular shape, the spire of this species 

 is still a little raised, and terminates in an obtuse and 

 rather large apex. The shell is thin (yet not so for its 

 genus), has but little lustre, and is of a scarcely semitrans- 

 parent pale olivaceous or reddish brown hue ; its surface is 

 nearly smooth, but is marked with rather coarse wrinkles 

 of increase. The whorls, which are four in number, and 

 though depressed yet decidedly convex, are divided by a 

 profoundly impressed or subcanaliculated suture ; they are 

 of slow longitudinal increase, but the last volution enlarges 

 most perceptibly towards the mouth, where it occupies at 

 least one-third of the total diameter. The circumference 

 of the final turn is not angulated but well rounded ; so 

 likewise is the base, whose large umbilicoid cavity exposes 

 the whole of the volutions, whose arrangement is such, 

 that the last one does not fully clasp the preceding turn at 

 the aperture, but is merely attached to it, and not on the 

 same level. Hence the mouth of the shell, which occupies 

 about two-thirds of the entire length, and nearly two-fifths 

 of the basal diameter, projects below the general basal 

 level ; it is almost circular, and is neither marginated nor 

 expanded, but thin and simple. Both throat and um- 

 bilicus are alike devoid of sculpture. The outer lip slants 

 rather more above than below, Avhere it is peculiarly ar- 

 cuated, and forms one continuous curve with the pillar- 

 lip, which last is rather long, very thin, and curls slightly 



