282 Zoological Society, 



Var. ^. T. roseo-purpurascente, albo-maculatd, nigrescente fasciatd ; 



lahio detrito. 

 Long. 0-80 ad 0'84; lat. 1-04 ad I'OS ; conv. 0*68 ad 0-76 poll. 

 Hab. Jimamailan, isle of Negros : on stones in a mountain- 

 stream. Var. /3, Ginijeran, isle of Negros : on stones in a sluggish 

 river. Var. y and ^, island of Burias. 



Operculum of a Clithon, whitish or rather rosy externally, with 

 one or two circular striee in the centre ; of a livid rose-colour, spotted 

 with yellow on the interior. Two teeth : the first lahiellated, pointed 

 at the summit ; the lower one circular, narrow, striated lengthwise 

 and across, but faintly. Subapophysary canal spotted with livid 

 rose, showing below two remote angles, but slightly raised. 



17. Nerita Sowerbiana. N. testd suhglohosd, tenue striatd nigro 

 et alhido alternatim fasciatd ; fasciis nigris alho-articulatis, alhidis 

 maculis nigro -mar ginatis antics sagittatis ornatd; anfractihus tri~ 

 bus, convexis ; spird vix prominuld, rotundatd; aperturd obliqud 

 cinerascente ; labio subconvexo, lutescente, antice denticulato ar- 

 cuatoque. 

 Var. /3. T. cinereo-lutescente, maculis sagittatis ut suprci subzonatd ; 



ad suturam maculis arcuatis nigris ornatd. 

 Var. y. T. nigerrimd, maculis triangularibus albidis adspersd, ad 



suturam interdum subspinosd. 

 Var. B. T. nigerrimd, maculis raris subpunctatd, zonis duabus lutes- 



centibus cinctd, ad suturam subspinosd. 

 Long. 0-56 ad 0-60; lat. 0-64 ad 0*72; conv. 0*48 poll. 

 Hab. Sinait, province of North Ylocos, island of Lu9on : on the 

 stony bed of a small river. Var. /3, y and ^, island of Guimaras : found 

 in a small stream on rocks. 



Operculum of a Clithon, deeply hollowed with a circular stria in 

 the centre, zoned transversely with bluish in the anterior portion of 

 its external surface ; the interior of a yellowish or livid rose-colour : 

 upper tooth citron, short, obtuse, united to the lower one, which is 

 smooth, circular, striated lengthwise and across by a short plate, 

 which is subsinuous anteriorly. 



I see no difference among all the varieties which I unite to this 

 Nerite, except those of colour. The characters of the operculum 

 are the same. 



I have very great satisfaction in dedicating this species to that 

 scientific conchologist, Mr. G. B. Sowerby. 



18. Nerita Montacuti. JV. testd ventricoso-globosd, suprci me- 

 dium spinis brevibus coronatd, oblique striatd, lutescente, supern^ 

 et infrcL medium zonis nigris lutescente maculatis pictd ; supremd 

 latiore ; anfractibus tribus supern^ depresso-planis ; spird depresso- 

 convexd; aperturd dilatatd, rotundatd, albido-lutescente ; labio an- 

 gusto, medio concavo, margine denticulato, in centre arcuato. 

 Var. p. T. olivaced, maculis lutescentibus adspersd, ultimo an/ractu 



superne convexiusculo, labio denticulato. 

 Var. y. T. dilute olivaced, maculis pallidioribus nigro antice sagit- 

 tatis marginatisque ; ultimo an/ractu superne subconvexo, labio 

 edentulo, integerrimo. 



