﻿R I S S A. 



Species 11. (Mus. So«ei-by.) 



RissoA AUia.srAi,i'iUM. fl/.s-. (Acwr) trsU nihd, ad 

 apertnram apicomqun piirpurascfnti, semipcllu- 

 cidd, altlssimd, medio paulo inflato ; apice acu- 

 minato; anfractibus iti'pti'in ad novinii, snpi-non- 

 hm frequenter Imuiitndiiiiiliirr rii.<l:iti.<. nUinin 

 elorujato ; apertiird maijud. orai,}^ Inh'io •'.ijHnisii. 



Thk kar-I'ick RissoA. Shc-11 wliite, pui-plish at tlie 

 aperture and apex, semipellucid, very elevated, 

 a little inflated in the middle, apex acuminated ; 

 whorls seven, often longitudinally ribbed, last 

 elongated ; aperture large, oval, lip expanded. 



LiNN^ns, Systema Katiu-rr. 



Rifisoa acicula, Risso. 



Rissoa marginatum, Montagu. 



R. acuta, Uesmarest. 



Tlah. Mediterranean. 



These long-spired Ris.^iuv do not seem to differ 



generically from the more typical forms. 



Species ll'. (^lus. Sowerby.) 



Rissoa LABIOSA. Ji'/.<. teMi! t>ralo-,irHiiiiiial,}. l.-imi, 

 semipclluc.idd, aJhii-pui-j'ina-^r, nl i, h-nlrr rnslnlii : 

 apice acuvtiHatu ; anfrarfn iilh nm siiliuijhil", ri's/is 

 infra viedium di/icoiitinuit: ; ,rp^r^^lrd tidtijtid, 

 elongatd, aurlformi, lahio expamtn. 



'Phk MEMBR.4Nons RissoA. Shell ovate, acuminated, 

 thin, semipellncid, purplish white, slightly ribbed; 

 apex acuminated ; last whorl rather inflated, 

 ribs discontinued below the middle ; aper- 

 ture large, long, ear-shaped, outer lip expanded. 



MoMTAGU. Test. Brit. Vol. II. p. 400. 



//(;//. Great Britain, MediteiTanean. 



Species 13. (Mus. Sowerby.) 



Rissoa vknusta. Rik. tcsid f:uhpiira»iid(ilii. xiih- 

 viridi, ie.nui, apice ariiniiinitn, aiifnicHhiis trmiitri 



gatia ; apertvrd anriformi, lahiv crpansn, infiis 

 niarglne acufo, extih raricnso. 



Thk HiioAU-Lii'PED Rissoa. Shell rather pyramidal, 

 greenish, thin ; apex acuminated ; whorls finely 

 ribbed, last rather ventricose. smooth below 

 the middle ; aperture ear-shaped, lip expanded. 

 inside liaving a sharp edge, outside varicose. 



i'lniirn. Knnm.' Moll. Sic. Vol. 1. p. 124, PI. XXIII. 



r. t. 



//.//-. Mediterranean. 



This does not appear to belong to any of the im- 

 merous varieties of Rlss-oa lahiata. A certain close- 

 ness of the outer lip and the distinct cessation of the 

 regular ribs at the middle of the last whorl serve to 

 distinguish it. 



Spei-ies 14. (Mus. Sowerby.) 



RiSSOINA r.y.LATA. ]u'.^. ( 7w«../;«0 IrsI,! lujr,, undald . 

 solid,;. ,dh.!, n.slis ,i,,d.,<;s sjjirahirr ninld, hni,/,. 

 Iud;,ini:t,r !„trr .-...l.is sirnil.l : „„h;,ri;ht>:< or/,., 

 „d latcra dn-lirlfn,,, .unrnurih,,. Iu..,j;i,n/i„„l,/, r 



■nstati.% C^^•//^• „,nJl'loti.< ,i ,i,,d, 



o/.m 



triijond, lahio e.rh-nio (■ca.s-si/, creiiiilato. 



Tni; iMBOSSED Rissoina. Shell pyramidal, solid, 

 white, spirally girt with nodose ribs, longitudi- 

 nally striated between the ribs; whorls eight, 

 sloped at the sides, upper longitudinally ribbed, 

 ribs angular and nodose; a])ertnre subtrigonal. 

 outer lip thick, erenulated. 



A. AiiAMS. Proc. Zool. Soc. 1851, 267. 



h';..„an, striata, Quoy. 



Itah. Siguijor. 



Species 15. (Mus. Marrat.) 



Rissoa riN.iii.i.us. A'-V. trsfd pijramldntd, la ri.jafd, 

 rel hrltrr ,,,1 .alitrr atrial,!, f„lrd, raslaar,..!,;- 



'liinl aarrn, 'cliunello ralidd. labia cxivnui ohtusi 



eoHatia, uiti 



