Scalaria. 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. Mm. Conch, t. cclx. f. 4.— Co- 

 ral Rag. 



Gen. LII. SCALARIA. — Spire produced ; transverse ridges 

 on the body-whorl continuous with the pillar. 



- 259- S. Clathrus. — Whorls 10, pointed, crossed by about 



ten regular continuous ribs ; the intermediate spaces smooth. 



Cochlea variegata, List. Conch, t. nlxxxviii. f. 51. Bor. Corn. 276. t. 

 xxviii. f. 9. — Turbo clath. Perm. Brit. Zool. iv. 129. t. lxxxii. 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. Dlxxxviii. f. 51. lower figures. — Turbo clath. Walk. Test. 

 Min. 12. t. ii. f. 45. Maton and Racket, Linn. Trans, viii. t. v. f. 1. — 

 Mont. Test. Brit. 297 Not common. 



Length about half an inch, breadth about T %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 ; lips 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 Trevetyana, Leach 

 MS." I have not seen any specimens, or met with any description of this 

 species. 



EXTINCT SPECIES. 



1. S. similis.— Whorls about 7, contiguous; spire with 5 or 6 rounded trans- 

 verse elevations, close to each other, and somewhat decussated, the lowest 



