﻿R I S S X. 



Plate Vlll. 



Species G6. (Mus. Brit.) 



RlSSOA PTEAMIDALIS. Ris. (Uissiiina) tt'std subpJipcn- 

 fonni, pallide fulvd, suhventrkosd, ohtusiusculd ; 

 anfractihits sex, ireviusculw, costis eleganter 

 flexuosis, longHudinaUhis Iwvibus h'rald ; apertnrd 

 subaurtformi, lahlo externa crasso, columella sub- 

 plicald. 



The pyramidal Rissoa. Shell somewhat pupa-shaped, 

 pale fnlvous, rather ventricose, rather obtuse ; 

 whorls six, rather short, ridged with elegantly 

 flexuous longitudinal ribs ; aperture somewhat 

 ear-shaped, outer lip thick, columella with averj 

 slight plait. 



A. Adams. Proc. Zool. Soc. 18.51, p. 26.'i. 



Hab. Baclayon, Isl. Bohol, Philippines. 



Species G7. (Mns. Brit.) 



Rissoa memdranacea. Bis. testd tenia, corned, altissimd ; 

 anfradibux septem, lateraliter subcomprcssis, 

 apicalibiis atteiiuatis, ultimo brevi ; apertiirii 

 auriformi, aniice ej'pansd, sxwrelrorsd, columella 

 subjlexuosd, brevi, labia externo expanso. 



The membranods Rlssoa. Shell thin, horny, very 

 elevated ; whorls seven, laterally subcompressed, 

 apical attenuated, last short; aperture ear-shaped, 

 anteriorly expanded, rather mclined backwards, 

 columella rather flexuous, short, outer lip ex- 

 panded. 



LoVEN ? 



Rissoa labiosa var. Auct. 



Hab. Black Sea and Jlediterranean. 



The more elevated varieties of Rissoa lahiosa do 

 not seem to approach the slender form and light tex- 

 ture of this species. 



Species 68. (Mus. Brit.) 

 Rissoa S.mitiiii. B/.<. (Rissoina) tcsfd albd, pared, 

 solidd, piijramidatd ; anjractibus septem, convexis. 



costatis, costis longititdinalibus, leviter aretiatis, 

 iiiterstitiis spiraliter striatis, ultimo anfractu infra 

 spiraliter costatd ; ajwrturd xnhtrigond, labia 

 externa crasso, cohuuill'i -■,-, !>,<,;, uhtusc uniplicatd. 



Smith's Ris.soa. Shell white, small, solid, pyramidal ; 

 whorls seven, convex, ribbed, longitudinal ribs, 

 slightly curved, interstices spirally striated, last 

 whorl spirally ribbed below ; aperture somewhat 

 trigonal, outer lip thick, columella thick, with a 

 binnt plait. 



Angus. Proc. Zool. Soc. 18G7, p. 114. 



Hab. Port Jackson, Australia. 



Species (")',•. (Mus. Brit.) 



Rissoa turricula. Kis. (Rissoina) testd riibrofmcd, 

 parvd, solidd, pi/ramidatd, acuminatd; anfracti- 

 bus octo, prominentibus, supra, medium subangu- 

 talis, ci:4atis, nistis pmiri.'; medio subangvlatis, 

 intrrsliliis loiiu'csiiiir ,s7;-/.///n ,• ,tp,rtiirdsemilunari, 

 lahio extern,, cra^,'„. ,:,l„„i.elld ,-raxsd, brevi. 



The little turret Rissoa. Shell red-brown, small, 

 solid, pyramidal, acuminated; whorls eight, 

 ])rominent, rather angular above the middle, with 

 interstices very finely striated ; aperture semi- 

 lunar, outer lip thick, columella very thick, short. 



Angus. Proc. Zool. Soc. 



Hab. New South Wales. 



The whorls are more prominent than those of 



Rissoa Smithii, and, with the ribs, more angular. 



Species 70. (Mus. Brit.) 



Rissoa crassa. Bis. {Rissoina) testd solidd, ruhro- 

 j'ulvd, brevi, obtusd; anfractibus septem, brevibtis, 

 lateraliter bubcompressis, longitudinaliter costatis, 

 codis leviter arcuatis, ultimo anfractu infra Imvi- 

 gato; aperturd rectiiisculd, columelld crassd, brevi. 



The thick Rissoa. Shell solid, red fulvous, short, 

 obtuse ; whorls seven, short, laterally rather 



