From the time tlie Crinoids which form the subject of this Memoir 

 came into my hands, I have been in constant correspondence with my late 

 friend, Philip Herbert Carpenter, regarding the many points of interest 

 suggested by their discovery. 



I can now only have the melancholy satisfaction of inscribing to his 

 memory a monograph which I had hoped to dedicate to him as an expres- 

 sion of my admiration for his researches in a field where we had long 

 been fellow workers. 



ALEXANDER AGASSIZ. 



