﻿RISSOA.— Plate IIT. 



lumldo ; aper!urd snhriifiindd, superiie jtrope 

 suluram, angulaid. 



Thk bug-shaped Rissoa. Shell white, subfusiform, 

 spirally prominently ribbed, interstices deep ; 

 above the middle, longitudinally very strongly 

 crenulately ribbed ; spire acuminated ; whorls 

 channelled above the suture, last tumid in the 

 middle, aperture rather rounded, angular near 

 the suture above. 



FoKBES. Brit. Moll. 



Huh. Britain. 



Species 26. 



Rissoa Zetlandica. Ris. (Alvania) testa cvato-sub- 

 Hovgatd, pallide fidvd, xplrd. tnrritd, (nifractihus 

 siilh/iniilr'ifi^. ntll'lr rioihtso-coiftatis, cancellatis ; 

 ultiiiiii infn) r,ii-i,,iil:: : , I ju- rtiird brevi, suhroturidd, 

 rjiluiiirlhi fiiijirnir tinii'nlii, Icihio exteriio crasso, 

 rrenulato. 



The Zetland Rissoa. Shell ovate, rather elongated, 

 pate fulvous, spire turreted, whorls rather square, 

 cancellated with strong nodose ribs, the last 

 keeled below ; aperture short, rather rounded ; 

 columella tumid above, outer lip thick, crenu- 

 lated. 



MCNTAGU. Testacea Britannica. Mont. Trans. Linn. 

 Soc. Vol. XI. p. l'.>4, PI. XTII. f. 5. 



Bksoa cyclostomata. Recluz. 



Tlih. Great Britain. 



Species 27. (Pig. a, 6, c, Mus. Sowerby.) 



Ris.-idA ULV.B. Ris. {nijdrohia) testa fulvd, trocMformi, 



snhdd, hvrl.^pinl antuiiiinta, ,-l,T,,ln. .uifnidlhns 

 pl^timhit:^, siitiin! //(.■/>,; .i.j,.i,-^iti.<. iilfiiiin leviter 

 anijiihitii; ujnrtiu;! nral,!, hilii.i i,ifrr,n> iiitegro. 

 The sea-weed Rissoa. Shell fulvous, trochus-shaped. 

 solid, smooth ; spire acuminated, raised ; whorls 



flattened, separated by an incised suture, last 

 slightly angular ; aperture ovate. 

 Pennant. Brit. Zool. Ed. 4, Vol. IV. p. 132. 



R;ss,',< x><l„i„<h;i;r.il„, Berkeley. 

 Rlssn^, ]:„rl,r;. .ictlVeys. 

 Hah. British .oasts. 



Species 28. (Mus. Sowerby.) 



Rissoa semistriata. Ris. {Ginyula) parvd,fuivd, ma- 

 culis in seriehus, tribiis cuKtaiieis, snhquadratis 

 cinctd ; spiraliter striafd : aufnirtilDin ijuiuiiiie, 

 plaidusculis ; ultimo matjHu, snin-iiurilnis lirrilma; 

 apertiird .lubtrigond. 



The half-striated Rissoa. Shell small, fulvous, 

 banded with rather square chestnut s])ots in three 

 rows; spiiully striated ; whorls live, rather flat, 

 last large ; upper smooth ; aperture nearly 

 trigonal. 



Montagu. Testacea Britannica, Supp. p. 136. 



Rissoa pulchra, Johnson. 



Rissoa lri.<triata, Thompson. 



Rissoa s,d,s„lc.,ta. Pliilippi. 



Hab. Britain. 



Species 29. (Mus. Marrat.) 



Rissoa costulata. Uis. t: sfa jid,d, suhconicd, costis 

 nunjids, distaittihus. aio/nlatis armatd, spiralita- 

 striatd ; spird acimiiiiatd, anfraetihus sex, eleratis, 

 angulatis ; aperturd suhrotundd, margine crasso. 



The ribbed Rissoa. Shell fulvous, rather conical, 

 armed with large, distant, angular ribs; spirally 

 striated, spire acuminated ; whorls six, elevated, 

 angular; aperture rather rounded, margin thick. 



Alder. As of Risso, Ann. Nat. Hist. 



Rissoa si^nilis, Seacchi Cat. p. 14, 2. 



Rijisoa Gmrinii, Rev. Zool. Cuv. 1843, p. 7. 



Hab. Britain, France. 



