Zuohyicul Society. HT 



iineolatd, et maculis Unearibus luteis subseriatis pictd ; apice sab- 

 violas cent e ; labio triangvlari, antice arcuatim excavato. 

 Var. h. T. elongatd, lateribus compressd, dorso co/ivexo-fornicntd, 

 antice subacute, interdum truncato ; luteo-fu^cescente, maculis ob- 

 longis antice nigris acutis lateraliter lineolis tenuissimis obsoJetis- 

 que obunibratls pictd; apice interdum nigrescente, labio trianyu- 

 lari, luteo-fuscescente. 

 Var. e. T. oblongo-ellipticd, lateribus compressd, lineolis pallide 

 fuscis aut purpurasccRtibus, et maculis oblongo-conicis luteis pictd ; 

 radiis biuis , pallide luteis in medio dorsi notatd ; labio triangulari, 

 antice urcuato. 

 Var. a : long. 0-88 ad 1-08 ; lat. 0-44 ad 0-56 ; conv. Q-24 ad 0'48 

 poll. Var. /3 and y : long. 0-96 ad 1*04 ; lat. OGO ad 064 ; conv. 

 0-32 ad 0-36. Var. B : long. 0-52 ad 064; lat. 0-32; conv. 0-28 

 ad 0-32. 



Hob. Var. a, from Banguey, province of North Ylocos : on stones 

 in a mountain-stream. Var. /3, from Cagaj-an : on stones in a large 

 river. Var. d, from Baccara : on stones in a rapid river. Var. e. ? , 

 cum prsecedenti. 



All these varieties are very remarkable, and, with the exception 

 of var. c, whose operculum I have not seen, all certainly belong to 

 the same species. The operculum of Nav. liiieata is oblong, very 

 thin, pale yellow, a little inclined to pale green, rounded behind, 

 notched before, notch in an oblique line at the base. The left side 

 of this operculum is slightly arcuated in the centre ; the right side 

 almost rectilinear and limited by an apophysary tooth, very narrow 

 and a little prolonged anteriorly. Muscular impression triangular, 

 elongated, inclined obliquely to the left. 



9. Navicella Extrecastauxi, Recluz. Rev. Cuvier. p. 380, 

 No. 14. 



Var. /3. T. obovatd, nigro-purpurascente, concentrice et crebre lineo- 

 latd, maculis luteis conicis aut subquadrat is pictd ; apice purpura- 

 scente marginali, non exserto ; aperturd albido-cxrulescente . 

 Long. 0-80 ad 0-90 ; lat. 0-56 ad 0-60 ; conv. 0-20 ad 0-28 poll. 

 Hub. ad insulas Philippinas. 



Operculum almost square, of the form and sculpture of that of 

 A'«r. tessellata, offering however some characters which the state 

 of that which was submitted to me does not allow me to judge of 

 with certainty. Its colour is of a rosy white, and yellow in the cen- 

 tre. It is possible that the iV. Entrecastauxi may prove only an 

 oboval variety, with a marginal summit of i\^ tessellata. When I 

 shall have seen a greater number of specimens with their opercula 

 I may be enabled to pronounce with more certainty. 



It results from this examination of the Navicella collected by Mr. 

 Cuming, together with those I have had an opportunity of studying 

 up to the present time — 1st, that the number of known species of 

 this genus amounts at present to eighteen ; 2ndly, that the Asiatic 

 Islands is that part of the world which contains the greater number 

 of species; and 3rdly, that Polynesia is afterwards the most rich 

 locality in species of this genus. 



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