I 2 



reported .is British to the present time arc the 

 following eleven : 



urn. 



//< dgsonii .. Rat 



echettris* „ centt 



C. cribrosuS) W. Sm. = /a/to , Shadb. 



hibemicuSi .. augularis. 



( ' r/o/w, W. Sm. eximius. 



Thurctii % .. limbatus. 



= C. parvuluSt W. Sm. 



It would be premature to attempt at present phical 



distribution of the genus, as many species, such as some of 

 those which are local in the inland sea of Japan and elsewhere, 

 will no doubt prove, after further explorations in little-known 

 lis, to have a much wider range of distribution. At the 

 11 Antipodes " many new species will probably also yet be further 

 discovered, as man; ts in the Southern hemisphere have 



never as yet been examined for Diatoms. 



atrary to what has taken place with the Coscinodisci^ com- 

 paratively few species of this genus have been preserved in a 



state in the tertiary formations. This I attribute to the 

 single (not double) shell of the last and to their delicate structure. 



Let me be allowed to repeat again that I attribute but very 

 little importance to the "species" admitted in this paper. No 

 <me has less faith than I have as to their permanent existence, 

 either on paper or in Nature. The actual forms known to us 

 in a living State, or even in a fossil state, are, I sincerely believe, 

 only transient or fleeting intermediaries between the " so-called " 

 spe< ie.s of the past and the •• so-called " species of the unknown 

 future. A spe< ies, properly so speaking, should represent an organ- 

 ism from its beginning or first appearance on this earth until its 

 final end, including all the forms, variations, and transformations 

 it may have acquired or passed through during the whole of its 

 in time and space. As such, the "species" is and 

 must ever remain unknown to man, although its past history 



