282 Zoological Society. 



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



labia detrito. 

 Long. 0-80 ad 0-84; lat. 1-04 ad 1-08 ; conv. 0*68 ad 0-76 poll. 

 Hub. 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 Z, island of Burias. 



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

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

 with yellow on the interior. Two teeth : the first laraellated, 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 subglobosd, tenue striatd nigra 

 et albido alternatim fasciatd ; fasciis nigris alba-articulatis , albidis 

 muculis 7iigra-marginatis antice sugittutis ornatd ; unfructibus tri- 

 bus, convexis ; spird vix praminuJd, rotundatd ; uperturd ob/iqud 

 cinerascente ; labia subconvexa, lutescente, antice denticulata ar- 

 cuatoque. 

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



ad suturum maculis arcuatis nigris ornatd. 

 Var. y. T. nigerrimd, maculis triangular ibus albidis adspersd, ad 



suturam interdum subspinasd. 

 Var. E. T. nigerrimd, maculis raris siibpunctatd, zonis duabus lutes- 



centibus cinctd, ad suturam subspinasd. 

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

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

 stony bed of a small river. Var. /3, y and d, 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. N. testd ventricoso-glabosd, supra me- 

 dium spinis brevibus coranatd, oblique striatd, lutescente, supernt 

 et infrei medium zonis nigris lutescente maculatis pictd ; supremd 

 latiore ; anfractibus tribus superne depresso-planis ; spird depressa- 

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

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

 Var. /3. T. olivaced, maculis lutescentibus adspersd, ultima anfractu 



superni convexiusculo, labia denticulato. 

 Var. y. T. dilute olivaced, maculis pallidiaribus nigra antice sagit- 

 tatis marginatisqtie ; ultimo anfractu superni subconvexa, labia 

 edenttilo, integerrimo. 



