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distinct species. Of the recent one I have before me five specimens 

 which represent three varieties ; and in all these the volutions are wider 

 in proportion to their length, than the corresponding varieties of the 

 fossil ; their apertures are consequently larger and wider in proportion ; 

 their volutions are more rounded, their sutures more distinct ; in all of 

 them there exist more or less distinctly marked longitudinal ribs (which 

 are not to be seen at all in the fossil ;) and in all of them there are also 

 longitudinal striae between the tubercular ridge and the suture ; so that 

 here are no less than five characters in which the recent appears constantly 

 to differ from the fossil shell. Besides the above characters I may also 

 mention that the aperture of the recent is very different from that of the 

 fossil which may be easily proved by a comparative examination of the 

 lines of growth. 



I am disposed to think, taking the above characters in which the 

 recent are found thus constantly to differ from the fossil shells, in combi- 

 nation with the fact of the existence of nearly parallel varieties in both, 

 that the recent ought to be regarded as a distinct species from the fossi} 

 and in this view of the subject I propose the following as the diagnostics 

 of the two species. 



I. Melania inquinata, Defr. 



Tests, elongato-turrita tevi, anfractibus decern, gradatim crescentibus, 

 subconvexis, postice prop^ suturam angulatis, ad angulum tubercu- 

 latis, tuberculis depressis; antic^ plerumque lineis transversis non- 

 nuUis pliis miniisve elevatis, nonnunquam interruptis; inter angulum 

 et suturam planis ; sutura subinconspicua ; apertura ovata, posticfe 

 emarginata, antic^ dilatata; long. 2' 4, lat. 0'72 poll. 



2. Melania Philippinarum, 



Testa elongato-turrita, laeviter subgranosa, anfractibus convexis, longi- 

 tudinaliter subcostatis, postice prope suturam subangulatis, ad angu- 

 lum tuberculatis, tuberculis subdepressis, anticfe posticeque lineis 

 • transversis nonnuUis plus minusve elevatis, nonnunquam interruptis; 



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