﻿i: 1 S S () A. 



Gonus KISSOA. FrcminviU.. 

 Testa vinri'iia, .-.-y./nj/As )il,'rinu,/iir turrit. i. hrn's ,;! 

 costiita : .yiin! unuiiiiKilii, iqirrtiini s,-miniliiii(/ii 

 vd piinjor,,,;, ^Nl.r,ni.,i:rul„t,l r,! uit.'.jra : l.ituo 

 crtrnin j.l.'rinininr inrrnssido. Operculum r„r. 

 neum, .^uUplnilr. 

 Shell mariuo, spiral, genci-ally turretud, smooth or 

 ribbed; spiro acuminated; aperture half-round 

 or pyriform, slightly cliannelled or entire ; outer 

 lip for the most part thickened. Opereulnm 

 horny, sabspiral. 

 The above description and the following mono- 

 graph are intended to include the genera Rissoa, 

 Altniiia, liissiitna, Hijdruhia, and other genera, which 

 have been separated but not very well defined, and 

 which at least require more careful revision than has 

 yet been accorded to them, and which it is not within 

 the scope of this work to give. The Iiinsuv or 

 ' Rissoida- ' are found in all parts of the world, ge- 

 nerally in shallow water anion? seaweeds. 



spiral striip, t'ulvous, with broad brown 

 spire pyramidal, whorls rather convex,; 

 ratlier short, onter lip white, crenulated. 



Riss,,. Kur. Mer. PI. IX. f. 156. 



Turhn cunr,: Linna-us. 



h'is.<..,t Fr,mi„r;n:;,, Risso. 



liissiui (/niuiiliita, Philippi. 



lils.iiin iniiiiimlUatii, Risso. 



Tlah. Britain. Mediterranean. 



bands ; 

 pertiire 



Species 3. (Mt 



Ma 



■att.; 



Rissoa Mo.vxAr.Ur. Riss. tedd fused, Ir.'riiisruld, rusti.' 

 pnurix rudl- crcnidatis srulptd ; spi'rd. prvdurtd, 

 pi/ramidatd ; anfractihus senis, (■uiwi'.cinnciilis ,- 

 iiperturd suhrotundd, marguie crenulato. 



Montagu's Rissoa. Shell brown, rather short, sculp- 

 tured with few, coarsely crenulated ribs ; spire 

 produced, pyramidal ; whorls six, rather coii- 

 ve.\ : aperture ratlier rounded, margin erenu- 



Species 1. (Mus. Sowerby.) 



Rissoa (-oina) SOALAHOIDES. Bis. tesid alhd, nltissimd, 

 anfractihus senis, productis, media a injiilalis. ml 

 anrjulum plicatis ; aperturd fri mlniidd, iininjiiie 

 rrasso, rotunda, labio -interno distinctn, atijiisto. 



The ScAi.AkiA-SHAi'ED Rissoa. Shell white, very high; 

 whorls six, produced, angular in the middle, 

 plaited at the angle, aperture almost round ; 

 margin thick, round; inner lip distinct, narrow. 



C. B. Ada.ms. Shells of Jamaica. 



Hah. Philippines. 



Species 2. (Mus. Marratt.) 

 Rissoa RnROP.SA. Riss. U-std suhpijraiuidatd, cast is 

 numerosis longitudinalibus et striis spiralibus 

 sculptd, falvd, late fuseo-fasciatd ; spird pyra- 

 midatd, avfraclihiis ronvexiusculis ; aperfurn 

 lireviiiseuld, margine externa alio, crenulato. 

 The European Rissoa. Shell rather pyramidal 



Payhauhkau. Cat. iloll. Corse. PI. V. f. 13 14. 

 Hah. Jfediterranean. 



The sculpture resembles that of Rissoa Europa^a. 

 but the ribs are fewer, and more distantly crenulated. 



Species 4. (Mus. Brit.) 



Ris.soA Cr.MiNGH. Biss. testa turritd, alba, pi/rami- 

 datd, acute canceUatd : anfractibuji scptenis, altis, 

 rotundis ; idliiiKi iiijtntn ,■ aperturd suhtriffond, 

 infra suhcau,il ieulald, nianjine crasso, crenatv. 



Cuming's Ris.soa. Shell turreted, white, pyramidal, 

 sharply cancellated ; whorls seven, high, rounded. 

 last swelled ; aperture rather trigonal, with a 

 slight canal below, margin thick, crenated. 



Rkeve. Proo. Zool. Soc. 



Ilah. Philippines. 



sculptu 



'ith numerous longitudinal ribs and 



Species 5. (Mus. Brit.) 

 Rissoa BRUoniERi. Kiss, (-oina) testa pi/ramidald, 

 altd, alhd, solidd, costis subcurvis et sulcis distau- 

 tibus sculptis, spird productd, pijramidatd. an- 



