v-^ 



INTRODUCTION. 



In the 'Annals and Magazine of Natiu'al History' for November and December 1840 (vol. vi. pp. 165 & 

 275) I published a " Synopsis of the Genera and Species of the Class Hypostoma [Aslerias, Linn.) ; " and in 

 the ' Proceedings of the Zoological Society ' for May 25, 1847 (see part xv., and Ann. & Mag..N. H. xx. p. lU3j, 

 I described some new genera and species of Asteriache. 



The former paper was prepared as a prodromus to a work which I intend to prepare, containing figures of 

 all the genera and of most of the species of this class. 



The Plates now published were then prepared ; but I deferred the continuation of the work at the urgent 

 request of Professor Agassiz, who wished me to unite with him, and bring out the work under our joint 

 names, forming part of the series of his ' Monograph of Radiated Animals.' 



He appears to have had too many occupations to allow him to proceed even with the Part of the 

 work which was to have appeared first ; and my own occupations have since prevented me from resuming 

 the work ; so the plates have been laid aside. 



As I see no hopes of the work being now proceeded with by either Prof. Agassiz or myself, and as several of 

 the Plates represent species figures of which have not hitherto been published, I am forced to let them appear 

 as illustrations of the descriptions of certain species, and hope that they may be useful in that humble form. 



I may state that I have twice sent copies of the Plates to the late Professor John Miiller, the author of a 

 work on the species of Asteriada, requesting him to inform me whether he had described any of the species, 

 and, if he had, to send me the names which he applied to them ; but though he replied to other portions 

 communication, he made no observation on the Plates, further than to express his admiration of them ; so I 

 suppose that most, if not all, of them were new to him. 



The article in the 'Annals and Magazine of Natural History,' vol. vi. p. 1G5, contains a history of the different 

 arrangements of the family and the genera into which the species have been divided, with the names which 

 have been given to the group, arranged according to the dates of their publication ; and in the introdnctiou 

 to the second paper I gave a review of Professor J. Miiller and D. Troschel's paper in the Berlin Academy 

 Reports, and their work on the Starfishes published in 1842. 



