viii INTRODUCTION. 



There are, in the Hunterian Collection of the Royal College of Surgeons, a considerable 

 number of fossil Crustacea from the London Clay, belonging to the foUomng species ; 

 XantJiopiiis Leachii, X. bispinosa ;,?), Xanlldlitcs Bowerbankli, Gotiiochele ungulata, 

 Dromilites Lamarckii, Thenops Scyllariformis, Hoploparia GammaroideB, H. Bellii, 

 Archaocarabus Bowerbankii. These are aU from Sheppey, and constitute part of a 

 collection of fossils formed principally by Hunter himself, and now in the course of 

 arrangement in the museiun under the care of Professor Morris. It is very interesting to 

 find that, amongst the immense riches belonging to the recent creation, collected by our 

 greatest comjjarativc anatomist and physiologist, there are so many examples of the 

 " organic remains of a former \\'orld," most of which have since been, as it were, re- 

 discovered and described, without tlie least suspicion that even these ancient beings had 

 not escaped the grasp of that universal mind. 



To those gentlemen who have with the most unrestricted hberality and kindness placed 

 their treasures at my service, and especially to Mr. Bo\verl)ank and Mr. Wetherell, whose 

 unrivalled collections have formed the basis of tliis work, my thanks are cordiaUy rendered. 

 To Professor Sedgwick and Mr. BaiTctt, of Cambridge, to Mr. Wood\\ard, of the British 

 Museum, to Professor Morris, to Mr. Prestwich, and other friends, I am also greatly indebted; 

 and the imperfections of tliis monograph can urge no claim to indulgence from the want of 

 the kindest sympathy and assistance from those who had the opportunity of rendering it. 



