^0 i[)t <§uljsfnkis. 



An earnest desire was expressed at the commencement of this work to make the 

 Monograph as complete as possible, and I beg to return my best thanks to those kind friends who have 

 so readily and obligingly assisted me with the use of their specimens for that purpose. I have now to 

 repeat my request that if there be any species or extraordinary varieties unnoticed, amongst the Genera 

 already described, in the Cabinets of Collectors to which I may not have had access, or which I may 

 have overlooked, or that may have been recently discovered, if they will allow me to have them 

 introduced into the next and concluding portion, I shall be still further obliged. We shall then have 

 done our best to make known the 'Crag MoUusca ;' and I may here state, for the information of any 

 future investigator of the Crag Deposits, who may be desirous of verifying the types of what are herein 

 described, that I have given my entire collection of these fossils to the British Museum. 



S. V. WOOD. 

 March; 1853. 



