Zoological Society. 277 



pressis ; apice compresso-concavo ; aperiurd orhiculari, suhcontinud, 

 intus alhidd ; lahio latissimo, depresso-plano, fusco-aurantio, mar- 

 gine subarcuato, edentulo ; labio rotundato, superne et inferne 

 dilatato. 

 Var. /3. Testd nigrescente, immaculatd. 



Long. 1*52; lat. 1*84; conv. 1*04 poll. Aperturse altitude 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 Lugon : 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 w^hich is unique in the genus Nerita. 



2. Nerita squamjepicta. N» testd ovato-subhemisphcericd, supra 

 medium vix depressd, striis longitudinalibus remotis superne et an- 

 tice subarcuatis impressd, sub epidermide olivaceo maculis squami- 



formibus antice nigro-marginatis undique pictd ; apice rotundato- 

 obtuso ; aperturd extits ovatd, intits albido-carulescente ; labia 

 piano, lutescente, medio albo, antice tenue arcuatim denticulato. 

 Long. 1-16 ; lat. 1-44; conv. 0'88 poll. 



Hab. Agoo, province of Pangasinan, isle of Lu9on : 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, canaliculated lengthwise, 

 feebly striated transversely, yellowish. 



3. Nerita Petiti, Recluz, Rev. Cuv. 1841. p. 274. No. 24. 

 Var. /3. T. majori,fusco-castaned ; infime et superne ad suturam com- 



pressd et subcanaliculatd ; spird retusd. 

 Var. y. T. minori, fusco-nigrescente, sub oculo et lumine maculis 

 nigris diversiformibus notatd ; aperturd subrotundd, superne et in- 

 ferno dilatatd, intus 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. Nerita asperulata. N. testd ovato-elltpticd, striis intertextis 

 granulosis asperulatd, fusco-nigrd, sub oculo et lumine, lineis ni- 

 gris ramosis transversis intricatis notatd ; anfractibus 1^, superne 

 depressis ; apice prominulo, obtuso; aperturd rotundatd, superne 

 et inferne dilatatd, luteo-fuscescente ; labio piano -compresso, mar- 

 gine vix arcuato et tenue ruguloso. 



Long. 0-56 ; lat. 0-76 ad 0*84 ; conv. 0-40 ad 0*44 poll. 



