SCALARIA. 209 



S. CLATHRATULA, MoiltagU. 



Uniform snow white ; ribs extremely thin and very numerous, 

 their interstices quite smooth. 



Plate LXX. fig. 3,4. 



Turho clatliratidus, Mont. Test. Brit. vol. ii. p. 297; Suppl. p. 124. — Turt. 

 Conch. Diction, p. 208. — Dillw. Recent Shells, vol. ii. 

 p. 854.— Wood, Index Testae, pi. 31, f. 92. 

 „ clatknis, var. Ii, Maton and Rack. Trans. Linn. See. vol. viii. p. 171, 

 pi. 5, f. 1. 

 Scalaria clatkrattda, Fleming, Brit. Animals, p. 311. — Clark, Zoolog. .Journ. 

 vol. iii. p. 343 (animal). — Brit. Marine Conch, p. 157. — 

 Brown, Illust. Conch, G. B. p. 21, pi. 8, f. 13.— Blain- 

 viLLE, Fauna Franqaise, Moll. p. 317. — Sowerby, 

 Thesaur. Conch, vol. i. pi. 33, f. 47. — Searles Wood, 

 Crag Mollusca, p. 94, pi. 8, f. 19 (fossil). 

 „ mitMta, J. SowERBV, Min. Conch, pi. 390. f, 3, 4 (fossil). 

 „ pulcMla, Philippi, Moll. Sicil. vol. i. p. 168, pi. 10, f. 1 ; vol. ii. p. 145 ; 

 KiENER, Coq. Vivant. Scalaria, pi. 6, f. 19 ? 



This small and delicately fragile shell is of a produced 

 turreted shape, of an uniform pure and glossy semitrans- 

 parent white, and adorned with extremely numerous (we 

 have counted twenty-two on the body-whorl) and remark- 

 ably thin, but not much elevated, simple longitudinal 

 costellse. Although laminar throughout, they exhibit, if 

 possible, still greater tenuity at the top of each volution, 

 where they are neither angular nor peculiarly prominent ; 

 they are scarcely at all oblique, and are divided by a pro- 

 found and but little slanting sutural line. Their intervals 

 are much broader, and quite smooth. The whorls, which 

 commence in a fine but not much pointed apex, and gra- 

 dually increase in length, are nine in number, of moderate 

 roundness, and rather short, the width of them being more 

 than twice their breadth. The body, for the most part, 

 only occupies one-fourth of the dorsal length ; the base 



VOL. HI. E E 



