302 MOLLUSCA. PECTINIBRANCHIA. Turritella. 
212. P. decussata. — Whorls eight or nine, strongly striated 
transversely ; minutely striated spirally. 
Helix dec. Mont. Test. Brit. 399. t. xv. f. 1 — On the shore at Wey- 
mouth, Mr Bryer. 
Length j^ths of an inch ; breadth ^^th ; white, slender ; whorls nearly 
flat, the separating line extremely fine ; aperture narrow, suboval, contract- 
ed at both ends ; outer-lip somewhat expanded, and a little thickened at the 
back ; inner lip slightly replicated. 
213. P. pallida. — Whorls six or seven, smooth ; outer-lip 
arcuated. 
Turbo pal. Mont. Test. Brit. 325. t. xxi. f. 4. — In sand, Salcomb Bay. 
Length |th of an inch ; breadth fds less ; slender, tapering to a fine point ; 
whorls separated by a well-defined line ; aperture suborbicular, a faint du- 
plicature on the pillar-lip, forming behind a small cavity. 
In the Mineral Conchology, the following fossil shells are referred to the 
genus, though it is more probable that they belong to Limnea or Paludina. 
1. P. orbicularis. — Conical, acute, smooth ; whorls about six, ventricose ; 
aperture nearly round. — Sower. Min. Conch, t. clxxv. f. 1. — Freshwater Lime~ 
stone^ Shalcomb, Isle of Wight. 
2. P. angulosa. — Conical, smooth ; whorls subcarinated ; aperture nearly 
round — Sower. Min. Conch, t. clxxv. f. 2. — Along with the last. 
3. P. minuta. — Elongated, smooth ; whorls five or six ; obscurely squared ; 
aperture oblong. — Sower. Min. Conch, t. clxxv. f. 3 — Along with the last. 
Gen. XLIX. TURRITELLA. — Shell elongated ; the whorls 
numerous, produced ; aperture wide ; the pillar-]ip slightly 
rounded. 
214. T. terebra. — Whorls about sixteen, with numerous spi- 
ral ridges. 
Buccinum tenue. List. An. Ang. 161. Conch, t. Dxci. £ 57. Turbo Ter. 
Linn. S. Syst. i. 1239. Penn. Brit. Zool. iv. 130. t. Lxxxi. f. 1 13. Mmt. 
Test. Brit. 293 — Common. 
Length sometimes exceeding two inches ; breadth of the body-whorl half 
an inch, of a reddish or purplish brown ; whorls sometimes eighteen in num- 
ber, ending in a fine point ; the larger whorls rounded, with five or six pro- 
minent ridges, besides smaller ones, crossed by the layers of growth. In the 
young shells the ridges are less numerous, and the anteal edge of the body- 
whorl is flattened. The aperture, in young shells, is subquadrangular ; in an 
old specimen the outer lip is round and thin, and the pillar-lip nearly straight. 
The animal is yellow, striped with dusky, with the tentacula short. — This 
species resides in deep water, but is frequently thrown ashore after storms. 
215. T. exoleta. — Whorls about twelve, spirally striated, with 
two broad rounded spiral ridges. 
Cochlea variegata. List. Conch, t. DXci. f. 58. — Turbo exol. Limi. Syst. i. 
1239 — Turbo cinctus, Bon. Brit. Shells, t. xxii. f. 1. Mont. Test. 
Brit. 295 — On the English coast, rare. 
