﻿RISSOA.— Plate X. 



Species 91. (Mns. Brit.) 



R.ISSOA (oina) NiVEA. Ris. testa si.ib}>ijramtdaUi, costis 

 oblique flexuosis ovnatd ; spird elevatd, aplce 

 acuminato ; ultimo anfractu infra spiraliter cos- 

 tato, aperturd infra suhqiiadratd ; columelld parvd, 

 breviuseuld ; labia externo incrassato. 



The snowy Bissoa. Shell subpyramidal, ornamented 

 with obliqaely flexuous ribs ; spire elevated, 

 apex acuminated, last whorl spirally ribbed 

 below ; aperture rather square belotv ; columella 

 small, rather short ; outer lip thickened. 



Ahthur Adams. Proc. Zool. Soc. 1851, p. '2Gb. 



Hab. Australia. 



Species 92. (Mus. Brit.) 



Ri.rsOA (OINA) albida. Ris. testa pymmidatd, acumi- 

 iiatd, alba, vel fulvd, semipellueidd, temii; uUimo 

 anfractu sub inflMo. Imvigato, alteris costatis, versus 

 apieem attenuatis ; aperturd subtrigond, columella 

 brt'L-i, truncaid, labio externo crassu. 



The whitish Rissoa. Shell pyramidal, acuminated, 

 white or buiT, half-ti-ansparent, thin ; last whorl 

 a little inflated, smooth, the others ribbed, 

 attenuated towards the apex; aperture rather 

 trigonal, columella short, truncated, outer lip 

 thick. 



C. B. Adams. Shells of Jamaica. 



Uab. West Indies. 



Species 93. (Mus. Brit.) 

 Rissoa (oina) ljjvissima. Ris. testa solidd, breviler 

 pyramidatd, jyalUdi; fulvd, politd; spird acumi- 

 iiatd, avfractibus rectilaieralibus ; aperturd sub- 

 trigond, parvd, cohimelld crassd, brevi, truncatd. 



The very smooth Rissoa. Shell solid, shortly pyra- 

 midal, pale fulvous, polished ; spire acuminated, 

 whorls straightened ; aperture rather trigonal, 

 small, columella thick, short, truncated. 



C. B. Adams. Shells of Jamaica. 



Hab. West Indies. 



Species 94. (Mns. Brit.) 



Rissoa (oina) Catesbyana. Ris. testa parvd, pyni- 

 inidald, fused, breviuseuld, costis oblique flexuosis, 

 validis ornatd ; spird brevi, anfractibus convexis ; 

 aperturd semilunari, labio interna superne incras- 

 sato ; columella brevi, arcuaid, labio externo pro- 

 ducta, incrassato. 



Catesby's Rissoa. Shell small, pyramidal, brown, 

 rather short, ornamented with obliquely flexuous 

 strong ribs ; spire short, whorls convex ; aperture 

 semilunar, inner lip thickened above ; columella 

 short, arched ; outer lip produced, thickened. 



D'Orbiony. Shells of Cuba. 



Rissoa scalarella. C. B. Adams. 



Hab. Jamaica, Cuba. 



Species 95. (Mns. Brit.) 



Rissoa (oina) princeps. Rig. pyramidatd, attenuatd. 

 altd, albd, acuminata; anfractibus tenuissiwe 

 costatis et striatis ; ultinia ihiiiyntn, infra Ixvigatu; 

 aperturd subtrigond, laliin r.iirnm tmm. 



The Prince Rissoa. Shell ]iyramidal, attenuated, 

 elevated, white, acuminated ; whorls finely 

 ribbed and striated, last elongated, smooth 

 below; aperture snbtrigonal, outer lip thin. 



C. B. Adams. Shells of Jamaica. 



Hab. Jamaica, West Indies. 



