﻿RISSOA.— Plate XII. 



Species 111. (Mus. Watson.) 



RissOA NovAEENsis. Bis. testd panel, hreviier ovato- 

 coHicd, crassd, pallidissime fulvd, costis longitudi- 

 nalibus frequentihus liratis paulo arcuatis, infra 

 medium desinentibus, et liris spiralibus tenuihus 

 sculptd, inter castas hiseriatvm fusco-maculatis, 

 infra maculas spiraliter tricostatd; anfractibus 

 qnatemis, brevibus, apicali rotunda, ultimo magna; 

 aperturd suhrotundd, labia crasso, rotuudo. 



The Notaea Rissoa. Shell small, shortly ovate- 

 conical, thick, very pale fulvous, sculptured with 

 numerous ridged ribs a little curved, ending 

 below the middle and slender spiral ridges, 

 spotted with brown in two rows, three spiral 

 ribs below the spots ; whorls four, short, apical 

 rounded, last large ; aperture rather round, lip 

 thick, rounded. 



Watson. Proc. Zool. Soc. 1873, p. STT, PI. XXXV. 

 f. 13. 



Hcdi. Madeira. 



Named after a frit;-;ite with which the shell had 



nothing to do. 



Species 112. (Mus. Watson.) 



liissoA Watsoni. Bis. testd parvd, tenuiusculd, troelii- 

 formi, liris spiralibus pramincntihus rotundis 

 cinctd ; anfractibus quaternis, apicali semirotundo, 

 duobus medianis angulatis rwjasa-costatis, inter 

 castas castaneo maculatis, ultima magna, angtdata, 

 supra unguium planulato, longitudinaliter costato, 

 inter castas rubro-maculato, media et infra spiraliier 

 solum castato, costd labiali liaud margincin altin- 

 genti. 



Watson's Rissoa. Shell small, rather thin, trochus- 

 shaped, girt with spiral prominent ridges ; whorls 

 four, apical semirotund, two middle angular, 

 rougbly ribbed, last large, angular, flattened, 

 and longitudinally ribbed and spotted with red 

 between the ribs above the angle, only spirally 

 ribbed in the middle and below ; labial rib not 

 reaching the margin. 



Schwartz. Proc. Zool. Soc. 1873, PI. XXXV. f. 11. 



JLil. Madeira. 



Species 113. (Mus. Watson.) 



Rissoa peeminima. Bis. testd parvd, oblongd, alld, 

 opaed, latvigatd ; anfractibus quaternis, siibelevaiis, 

 lateraliter rotundatis, ultimo magna, anguste urn- 

 bilicato; aperturd subovatd, margine fere integro, 

 ieiiuinsciilo. 



The very small Rissoa. Shell small, oblong, white, 

 023aque, smooth ; whorls four, rather raised, 

 laterally rounded, last large, narrowly umbili- 

 cated ; ajjerture rather oval, margin nearly entire, 

 rather thin. 



M.\NzoM. Proc. Zool. Soc. 1873, p. 385. 



Eissoa ahjecta. Watson. 



Hab. Madeira. 



Species 114. (Mus. Watson.) 



Rissoa albugo. Bis. testa parvd, tenui, semipellueidd 

 suhovato-trocMfarmi, fasciis lineisque puncturum 

 rubrarum pictd ; anfractibus quinis, brevibus, con- 

 vcjns ; aperturd magna, antice rotunda, postice 

 acuminatd, colmnelld altd, subarcuatd. 



The peaelt film Rissoa. Shell small, tliin, semi- 

 pellucid, subovate-trochiform, painted with bands 

 and lines of red spots ; whorls five, short, con- 

 vex ; aperture large, anteriorly rounded, poste- 

 riorly acuminated, columella high, rather arched. 



Watson. Proc. Zool. Soc. 1873, p. 379. 



E,ih. ^Madeira. 



The colouring consists in spii'al and perpendicular 



rows of minute red spots. 



Species 115. (Mus. Watson.) 



Rissoa GliiBERULA. Bis. testd. brevi, quadrangular!, 

 ,nh\M, albd, vel puUiJr f.lrd, ^pimJilcr an./Hsic 

 frifasriatd, costis vui,j,n^ „l,i;,j„; jl, ■,„,,.;.<. .Ii<fn,itl- 

 biis, ad suturarn acumi initio niiiiiifil,.^pird graJnta, 

 .iiiturd concavd; anfractibus brevissimis, ultimo 

 infra casta spirali validd desinenti, late umbili- 

 cato; aperturd parvd, perfendieidariter ovatd, 

 margine tenui, antice prmninonti, costd labiali 

 latissimd, crassd. 



The little humped Rissoa. Shell short, quadrangular, 

 solid, white or pale fulvous, with three spiral 

 narrow bands, strengthened with large obliquely 

 flexuous distant ribs, pointed at the suture, spire 

 gradated, suture concave; whorls very short, the 

 last ending below in a solid spiral rib, broadly 

 umbilicated ; aperture small, perpendicularly oval, 

 margin thin, prominent in front, labial rib very 

 broad, thick. 



Watson. Proc. Zool. Soc. 1870, p. 371, PI. XXXIV. 

 f 7. 



Hab. Madeira. 



This beautiful little shell has the general appearance 



of a Cancellaria, but is a true Eit^sua. 



