iv 



graphical grouping of species, as the general series. And finally, for conve- 

 nience of reference, an alphabetical list of all varieties noticed in the cata- 

 logue has been added. 



This Catalogue while shewing what our collections at present contain, 

 may also be taken as indicating equally our wants, in this group of fossils. 

 And we would solicit the contribution of any such desiderata. Those only 

 who have been compelled to work out paleeontological investigations in this 

 country, deprived of all those facilities for ready comparison and reference 

 which most European capitals afford, can fully appreciate the value of such 

 series. And every addition even of a single authenticated species is the 

 addition of a valuable means of progress. 



Similar catalogues of other classes will follow. 



THOMAS OLDHAM. 



May, 1865, 



