144 CADULUS-DISCHIDES. 



II. Considerably contracted anteriorly ; slits deep and narrow ; 

 length 9 mill., about 6? times the greatest diam., dichelus. 



C. POLITUS (Searles Wood). PI. 27, figs. 90, 91, 92, 93, 94. 



Shell small and slender, thin, arcuate, considerably tapering; 

 translucent bluish-white, with many unequal obliquely transverse 

 lines and bands of opaque-white. Sculpture of fine, inconspicuous 

 growth-striae, running obliquely around the tube. Near the aperture 

 the tube contracts quite noticeably. Aperture oblique, round-oval, 

 a trifle wider than long ; peristome thin and simple. Apex bilabi- 

 ate, narrowly and deeply slit on each side, edges of the apical lobes 

 bevelled. 



Length 7'6, greatest diam. antero-posteriorly 0*81, laterally O81 

 mill. ; aperture, greatest diam. 0'67, least 0'63 mill. ; diam. at apex 

 0-31 mill. 



Mediterranean, from Sicily to Gibraltar. Atlantic : Morocco ; Can- 

 aries ; Portugal at Setubal Bay ; Gulf of Gascony ; Benzert Road, 

 Adventure Bank. Pliocene, Coralline Crag, England; Italy. 



Ditrupa polita S. V. WOOD, Ann. Mag. Nat. Hist, ix, p. 459, pi. 

 5, f. 14 (August, 1842). 



?? Dentalium pusillum PHIL., Enum. Moll. Sicil., i, p. 245 (1836), 

 ii, p. 206 (1844). 



Dentalium coarctatum PHIL., Enum. Moll. Sicil., ii, p. 208 (1844), 

 not of Lam. 



Dentalium Icsvigatum DE RAYNEVAL, v. D. HECKE & PONZI, 

 Catal. foss. du Mont Mario, Versailles, 1854 (not seen by us). Not 



D. IcKvigatum Schlotheim, 1830. 



Dentalium bifissum S. V. WOOD, Crag Moll., i, p. 190, pi. 20, f. 3, 

 a-b (1848). 



Dischides bifissum [its'] Wood, JEFFREYS, Ann. Mag. N. H. (3), 

 xx, p. 251 (1867) ; P. Z. S., 1882, p. 663. ARAD. & BEN., Conch. 

 Mar. Sicil., p. 117 (1870). WEINKAUFF, Conch, des Mittelm., ii, 

 p. 421 (1868). MONTS., Norn. Gen. e Spec. Conch. Med., p. 34 

 (1884). 



Dischides olivi Sc., JEFFREYS, Ann. Mag. Nat. Hist. (4), vi, July, 

 1870, p. 73. 



The anterior contraction is much more abrupt than in Dischides 

 belcheri or D. brevis. C. bifissuratus is a stouter, larger shell. The 

 present species was first well defined as Ditupa polita, but this name 

 has since been forgotten, and olivi, coarctatum and bifissum have been 



