10 



and I have shown that three of Mr. Stutchbury's species form either in- 

 ternal or external varices at various periods of growth. And though I 

 thus say, I do not intend to assert that these facts are to be taken as 

 conclusive against the establishment of the proposed genus, but only as 

 strongly unfavourable to it. 



I have thought it necessary to make these preliminary remarks, be- 

 cause the treatment I have experienced in consequence of my observa- 

 tions upon this subject, is such as would have prevented me from con- 

 tinuing to bring forward the numerous facts with which I am acquainted, 

 had I not been convinced of the necessity of fearlessly giving them 

 publicity even at the risk of exposing myself to such misrepresentation : 

 for these facts cannot always coincide with the opinions or preconceived 

 notions of certain classes of writers, the profound ignorance of some of 

 whom is only equalled by their arrogance.* 



I shall therefore now proceed to the subject of the present communica- 

 tion ; only premising that my aim and intention is alone the advancement 

 of the purity and exactitude of such Natural Sciences as may be in a greater 

 or less degree affected by my facts. The form in which I shall put my 

 observations will be that of a critical analysis of the various published 

 observations and assertions relating to the Melania inquinata o{ DeFrancCy 

 and I shall add such facts as I have had the opportunity of observing 

 whether corroborative or not of previously published opinions. In 

 order to avoid frequent references I have placed at the head of this arti- 

 cle the direction to all that has appeared upon this subject, down to this 

 present time, as far as I know of. It will be needful in the first place 

 to ascertain what are the precise characters of Melania inquinata accord- 

 ing to DcFrance; then I must enquire how far the yb55z7 shells given 

 under that name by Deshayes agree with the true Melania inquinata of 

 DeFrance ; next I must institute a careful comparison of this fossil 



that it might not actually have been detatclied by the sudden contractions. 

 of the animal upon being plunged inlo the strong spirit in which it was 

 preserved. 



• I do not intend to include among these writers either of the Mesjsrs, 

 Stutchbury. 



