ECHINOIDEA. I. 



d'Arcy Thompson (Dundee). By this j^resent I beg to offer my sincerest thanks to all these 

 gentlemen. Finalh- I had occasion for a short stay at the British Museum in August 1901. By the 

 genial friendliness of Prof. Bell I was enabled to examine a great many forms, especially original 

 specimens from the Challenger-Expedition. It will appear throughout my work, that this stay has been 

 of material importance to me, and my best thanks are due to Prof. Bell for his liberality. Still I have 

 to thank Dr. F. A. Bather (British IMuseum) for his excellent assistance in several literary questions. 



Copenhagen, January 1902. 



The Author. 



