RIflBOin 



anteriorly effuse or faintly channeled. Opercullim corneous, thick, 

 -emilunar, paucispiral. with a claviform process on the internal fare. 



(PL 'U 



The form of tlic operculum, and cHusc character of tin- base of 

 the a|HTtmv arc distinguishing features of this Lrroup. Tin- species 

 inhabit \vann and temperate 8688, arc world-wide in distribution, 



and over 1 HO Lfood species have been eliaracteri/.ed. There arc 

 -me secondary and tertiary specie. 

 Section IIissniNA . typical >. 



I. .niritiidinally nutate, with or without spiral stria-, aperture 

 produced below, without funicular rib on the lase. 1{. INCA, Orb. 



>er(iol) Kl^MM.INA. ( Jnllld. 1'^<)1. 



With funicular rib below. K. I-:IJ-:;ANTISSIMA, Orb. 



S,--iion Miri:.>Ti:i..MA. A. Ads. 1X63. 



Turreted. ovate, riinate, spire conic, whorls lonL r itudinally plicate ; 

 ajterture ohlonir, J^roduccd anteriorly, subcanali<'ulat(', inner lip 

 thickened, outer lip sini])le. K. I>.T;I>ALA, A. Ad. Japan. 



i-ui SCHWA KT/I 1:1. LA, Nevill. 1884. 



Aperture without basal einarirination. I{. r,i:vi:i:i:A, Mtg. 

 Seo^on Pii'^iNi-i-LA, Morch. 187(5. 



Shell reticulated by sube<|ual scul]>tur(' ; aperture profoundly 

 >inuated below. ( )perculuin denticulate posteriorly. 



R. RACKAIANA, d'Orb. 

 LOO /I:IMN ELLA, M'irch. l*7o'. 



Shell very fiiudy Longitudinally costellate and spirally striate; 

 aperture widened and eniar^inate below. 1!. IIKTUTI.ATA. So\\b. 



Section MOIICHII.I.I.A. Nevill. 1XX4. 



Upp<-r part of shell longitudinally ribbed, lower part smooth, or 

 spirally .-triate. II. I;K;ANTI-:A. Desh. 



M /! \.\\ \. II. A' A. Adams, lx.14. 



Shell white, solid, oj>ao j ue, poli.-hed, smooth or partly >triate; 

 outer lij) rather thick, often with one or more anterior internal lu- 

 ll. BBOWOT \\ A. <r< >rb. 



i T^ i:\MMH-:i. I.MII. I B, Nevill. 1> V t. 



Narrowly turreted. with spiral ribs, tubereulated below the suture. 



II. CN80LTTA, De>h. 



IIIA. Urusina. 1- S 7 ( .. 



Kiiibryniial shell -ini-tral; whorls cancellated; apert lire canali- 

 culated in front, lip varicose, dentate within, axis >ubj>ert'>rate. 



