68 Botanical Society of Edinburgh, 



15. RissoiNA NODiciNCTA, A. Adams. R. testa subulato-tur- 

 ritd, alba, solidd, anfractibus 10-12, convexis, longitudinaliter 

 plicatd, plicis angustis, distantibus, transversim tenuissime stri- 

 ata, in medio anfractuum cinguld elevatd ad plicas nodosa, or- 

 natd, suturd nodulis moniliformibus cinctd; aperturd semiovatd, 

 antice subcanaliculatd ; labio antice callo terminato; labro dila- 

 tato, extus incrassato, margine Jlexuoso. 



Hab. Isle of Capul, Philippines. Mus. Cuming. 



16. RissoiNA c^ELATA, A. Adams. R. testd subulato-turritd, 

 albidd, solidd ; anfractibus octo, convexiusculis, supremis cla- 

 thratis, ultimo cingulis elevatis, cequalibus, subdistantibus, 

 transversis, interstitiis lineis elevatis, longitudinalibus et trans- 

 versis, decussatim ornato ; aperturd semiellipticd, antice sub- 

 canaliculatd ; labio calloso ; labro antice dilatato, margine in- 

 crassato, subreflexo. 



Hab. Siquijor. Mus. Cuming. 



The two following species are true RissocB, characterized by the 

 simple aperture, which is not channeled in front, and by the absence 

 of the calcareous appendage to the operculum. Many species of 

 small shells have been inaccurately referred to Rissoa, some of which 

 belong, however, to entirely different families. 



Rissoa bella, A. Adams. R. testd turrito-subulatd, albd, 



solidd; anfractibus quinque, planiusculis ; spird apice obtuso, 



lineis transversis, elevatis, concentricis, confertis, ornatd ; 



-.. 1 aperturd ovali, antice integrd ; labio subcalloso ; labro sub- 



rf^'i'^ dilatato, extus mar ginato, margine Jlexuoso. 



Hab. Philippine islands. Mus. Cuming. 



Rissoa elegans, A. Adams. R. testd subulato-turritd, albd, 

 seynipellucidd ; anfractibus 7, convexiusculis ; suturd canalicu- 

 latd, lineis elevatis transversis concentricis et longitudinalibus 

 concinne decussatd ; aperturd ovali, subproductd, antice inte- 

 grd ; labio calloso ; labro antice dilatato, extus varicoso, mar- 

 gine acuto, subrejtexo. 



Hab. Philippines. Mus. Cuming. 



botanical society of EDINBURGH. 



The Society opened their Eighteenth Session on Thursday, No- 

 vember 10th, — 



Professor Balfour, President, in the Chair. > 



Dr. Balfour, in taking the Chair, alluded to the value of the Society 

 as a means of keeping up a friendly intercourse among those who 

 were prosecuting the science of botany. lie noticed the recent 

 researches in regard to the class of plants called Diatomacese, and 

 stated that a large microscopical collection had been made at the 

 Botanic Garden, and that the specimens would be exhibited during 

 the Session. 



