98 



20. C, LisTERi. (pi. xxiii.f. 22. 23.) Gray. Mus. Brit. 

 T. subgiobosa, crassiuscula, spira conoidea, subacumi- 



nata, anfractibus 4 — 5, rotundatis, Isevibus, iionnunquani 

 superne spiraliter obsolete striatis ; sutura distincta ; a])er- 

 tura circulari, peritremate subincrassato, superne angulato, 

 latere uml^ilicali calloso, callo umbilicum partim obtegente; 

 uml)ilico parvo, spiraliter striato. 



Shell nearly globose, thickish, spire conoidal, rather acu- 

 minated ; volutions 4 — 5 rounded, smooth, sometimes 

 obsoletely striated longitudinally, more distinctly so in young 

 specimens ; suture distinct ; aperture circular ; peritreme 

 somewhat thickened, angular at the upper part, spread- 

 ing on the umbilical side into a callus which partly covers 

 the small spirally striated umbilicus. Mauritius. 



21. C. LiGATUM. (pi xxiii, f. 24.) Lam. Anim. sans Vert. 

 T. tenui, subglobosa, spira conoidea, subacuminata ; 



anfractibus 5 — 6, rotundatis, obsoletissime longitudinaliter 

 et transversim oblique striatis ; sutiu-a distinta ; apertura 

 (urculari, superne subangulata ; peritremate tenui, paululvim 

 sub reflexo, latere umbilical! patente; umbilico parvOjleevissimo. 



Shell thin, subglobose, with a conoidal, rather acumi- 

 nated spire, consisting of 5 — 6 rounded volutions which 

 are very obsoletely striated longitudinally on the upper part, 

 these striae being obliquely crossed by other transverse strice 

 which are equally faint, the suture is strongly marked ; the 

 aperture is circular, rather angular at the upper part; 

 peritreme thin, very slightly reflecled, spreading so as partly 

 to cover the umbilicus on the inner side ; umbilicus small, and 

 together with the lower part of the volutions quite smooth. 

 The apex is of a dark colour. 



22.C.AFFiNE.(pl.xxiii. f. 25. 26) wo5. Turbo ligatus, Wood. 



T. tenui, subglobosa, spira conoidea, subacuminata; apice 

 obtuso ; anfractibus 4 — 5, rotundatis, leevigatis; apertura cir- 

 culari, superne subangulata ; peritremate tenui, latere umbih- 

 cali paululum reflexo ; umbilico parvo spiraHter sulcato ; oper- 

 culo laevigato, nucleo sublaterali. 



Shell thin, nearly globose, with a conoidal, rather acu- 

 minated spire, whose apex is obtuse ; volutions 4 — 5, 

 rounded, smooth ; aperture circular, slightly angular at the 

 upper part ; peritreme thin, ver}' slightly reflected on the 

 umbilical side ; umbilicus small, spirally grooved ; operculum 

 smooth, with a somewhat lateral nucleus. 



