200 CERITHIADJi. 



SPURIOUS. 

 0. cosTATUM, Da Costa. 



Stromhus costatus, Da Costa, Brit. Conch, p. 118, pi. 8, f. 14. — Pulteney, 

 Hutchins, Hist. Dorset, p. 42. — Donov. Brit. Shells, 

 vol. iii. pi. 94. — Mont. Test. Brit. vol. i. p. 255 ; Suppl. 

 p. 169. — Maton and Rack. Trans. Linn. Soc. vol. viii. 

 p. 142. — Rack. Dorset Catalog, p. 46, pi. 14, f. 14.— 

 TuRT. Conch. Diction, p. 165. — Dillw. Recent Shells, 

 vol. ii. p. 678. — Wood, Index Testaceolog.pl. 25, f. 43. 



„ turboformis, Mont. Test. Brit. Suppl. p. 110, pi. 30, f. 7. 

 Ceritliium cosUttum, Fleming, Brit. Anim. p. 357. — Brit. Marine Conch, p. 192. 

 — Hanley, Young Conch, p. 79. 



„ turhiforme, Fleming, Brit. Anim. p. 357. — Brit. Marine Concli. p. 193. 



„ Lafondii, Kiener, Coquilles Vivantes, Cerith. p. 97, pi. 24, f. 3 (as of 



MiCHAUD, Bull. Linn. Soc. Bordeaux, 1829, pi. 5, f. 7, 8, 

 which we cannot now refer to). 



„ amhitjiuum, Adams, Synopsis Conch. Jamaic. p. 4, (from types). 



Turreted, simply tapering, rather thin, not polished, of an 

 uniform chestnut brown when dead, but when alive of an iron 

 grey, with the raised sculpture, especially in the middle of the 

 whorls, of a paler cast, adorned with fine and somewhat curved 

 longitudinal ribs that vary greatly as to strength and number 

 (we counted seventeen on the penult turn of a characteristic ex- 

 ample) but are always narrower than their intervals, and more 

 densely disposed upon the lower volutions. These ribs sometimes 

 extend the whole length of each whorl, but more frequently 

 abruptly cease just before the profound or even excavated suture, 

 that, for the most part, is surmounted by a single slightly raised 

 generally interrupted spiral costella, which winds from the upper 

 corner of the aperture to nearly the anterior base of the outer lip, 

 and serves as a limit upon the body to the longitudinal ribs ; the 

 surface below it, when not traversed, as it often is, by an adjacent 

 similar but less prominent threadlike line, is smooth or nearly so. 

 Occasionally the continuity of the ribs is disturbed by two or 

 three obscure spiral sulci which give them a slightly granular 

 appearance. There are about eleven simply and moderately 

 ventricose whorls, which are usually a little angulated above ; 

 they are not furnished with varices except a single broad white 



