169 
f * Orbiculate seu subhemispherice. 
1. Nerira tasiosa (Sowerby). N. testd orbiculari, postice angus- 
tatd, fornicatd, crassd, maximd, striatd, fusco-viridescente, nigro 
et rufo obsolete variegatd ; anfractibus duobus ad suturam com- 
pressis ; apice compresso-concavo ; aperturd orbiculari, subcontinud, 
intis albidd ; labio latissimo, depresso-plano, fusco-aurantio, mar- 
gine subarcuato, edentulo ; labio rotundato, superne et inferne 
dilatato. 
Var. 2. Testd nigrescente, immaculatd. 
Long. 1°52; lat. 1°84; cony. 1:04 poll. Aperture altitudo 1°52; 
lat. 1°60 poll. 
Hab. Ad Insulas Philippinas; Tanhay, isle of Negros: in a small 
river. Var. 3, Agoo, province of Pangasinan, isle of Lucon: on 
stones in a rapid river. 
Two pyriform muscular impressions, and more forward than in any 
other species, are visible at the internal base of the columella, which 
has no trace of callosity. 
The upper tooth of the operculum is oblique, lamellated, with a 
strongly-cut crest, a character which is unique in the genus Nerita. 
2. Nerira squam#prcta. UN. testd ovato-subhemisphericd, supra 
medium vie depressd, striis longitudinalibus remotis superne et an- 
tice subarcuatis impressd, sub epidermide olivaceo maculis squami- 
Sormibus antic nigro-marginatis undique pictd ; apice rotundato- 
obtuso ; apertura extis ovatd, intis albido-cerulescente ; labio 
plano, lutescente, medio albo, anticé tenue arcuatim denticulato. 
Long. 1°16; lat. 1°44; conv. 0°88 poll. 
Hab. Agoo, province of Pangasinan, isle of Lucon: in a rapid 
river. 
Operculum similar to the Nerites, allied to N. pulligera ; subcon- 
vex above, finely striated lengthwise, of a whitish fawn-colour pos- 
teriorly ; rosy anteriorly, streaked with circular bands of a blackish 
blue; subconcave below, of a dirty green, spotted with rosy white 
at the anterior side. Two teeth: the upper one ovate, acute at the 
summit, reddish; the lower one circular, canuliculated lengthwise, 
feebly striated transversely, yellowish. 
3. Neriva Periti, Récluz, Rev. Cuv. 1841. p. 274. No. 24. 
Var. 6. T. majori, fusco-castaned ; infime et superné ad suturam com- 
pressd et subcanaliculatd ; spird retusa. 
Var. y. T. minori, fusco-nigrescente, sub oculo et lumine maculis 
nigris diversiformibus notatd ; aperturd subrotundd, supern? et in- 
Serne dilatatd, intis aurantid. 
Long. 1°40; lat. 1:96; conv. 1°16 poll. 
Hab. Cagayan, province of Misamis, island of Mindanao: on 
stones. Var. y, Agoo: in a mountain-stream. 
The operculum of this species differs from that of N. pulligera 
only in its paler colour. 
4. Nerira aspeRuLAtTa. UN. testd ovato-ellipticd, striis intertextis 
granulosis asperulatd, fusco-nigrd, sub oculo et lumine, lineis ni- 
