Scalaiua. MOLLUSCA. PECTINIBRANCHIA. 311 
Gen. MONODONTA. — Pillar-lip notched or suddenly in- 
dented, so as to exhibit an imperfect canal. 
1. M. muricatus. — Short, conical, whorls 5, with many equal muricated 
spiral ridges ; lip plaited — Turbo mur. Sower. Min. Conch, t. cclx. f. 4.— Co- 
ra/ Rag. 
Gen. LII. SC AL ARIA. — Spire produced; transverse ridges 
on the body- whorl continuous with the pillar. 
S59. S. Clathrus. — Whorls 10, pointed, crossed by about 
ten regular continuous ribs ; the intermediate spaces smooth. 
Cochlea variegata. List. Conch, t. Dlxxxviii. f. 51. Bor. Corn. 276. t. 
xxviii. f. 9. — Turbo clath. Penn. Brit. Zool. iv. 129. t. Ixxxu. f. 3. d. 
t. 3. a.— T. clathratulus, Don. Brit. Sh. t. xxviii. upper figures — ^Not 
common. 
Length about an inch and a half, breadth at the base half an inch ; colour 
usually white ; volutions rounded ; deeply divided by the separating line, 
across which the ribs are extended ; pillar behind imperforated. The body- 
whorl is destitute of the keel-like spiral ridge which distinguishes the S. la- 
mellosa of Lamarck, a species confounded with the preceding by Linnaeus. 
Animal mottled black and white ; discharges a purple dye ; snout produced | 
tentacula slender, black ; operculum coriaceous, black and spirally striated. 
260. S. clathratulus. — Whorls 8, obtuse, crossed by upwards 
of 15 regular continuous ribs, the intermediate spaces smooth. 
List. Conch, t. nlxxxviii. f. 5L lower figures. — Turbo clath. Walk. Test. 
Min. 12. t. ii. f. 45. Maton and Rackety Linn. Trans, viii. t. v. f. 1 . — 
Mont. Test. Brit. 297 — Not common. 
Length about half an inch, breadth about j^ths ; like the preceding, but 
more slender in its growth, the ribs more numerous and less elevated. 
261. S. Turtoni. — Whorls about 12, pointed, crossed by 
about as many ribs, interrupted by a separating line ; the in- 
termediate spaces spirally striate. 
Turba clathratus var. Don. Brit. Shells, t. xxviii, the lowest figure.— -T. 
Turtoni, Turton.^ Conch. Diet. 208. f. 97.— On the Irish and English 
coasts. 
Length two inches and a half, breadth three-quarters of an inch ; pale 
brown, with two or three spiral dark bands. Shell strong ; whorls rounded ; 
the ribs are but little raised, rounded, bent at the line of separation ; some are 
large, and longitudinally wrinkled ; Ups white, pillar-lip a little reflected. 
In a paper by Mr Winch on the Geology of Lindisfarn, (Annals of Phil. 
XX. 434.) there is a notice of a recent species of this genus from the neigh- 
bouring sea, and which is there designated, “ Scalaria Trerelyana., Leach 
MS.'’'* I have not seen any specimens, or met with any description of this 
species. 
EXTINCT SPECIES. 
1. S. smi/w.— Whorls about 7, contiguous ; spire with 5 or 6 rounded trans- 
verse elevations, close to each other, and somewhat decussated, the lowest 
