HISTOEICAL. 31 



Trimera, Tetramera, Pentamera, and Poljmera. The fallacy of this plan is 

 well shown if we consider that the smaller number of basals is simply the 

 result of anchylosis of two or more of the original five plates; and that in 

 many cases it brings together the most diverse forms, while forms which 

 naturally belong together are widely separated. We need only refer to 

 the highly differentiated Calceocrinidae, of which some species have four 

 basals, and others but three. In the genus Plati/crinus the normal number 

 is three -, but in many cases they are anchylosed into a solid disk, leaving 

 no trace of suture lines. Under Miller's classification many species, and 

 often individuals of the same species, would have to be referred to different 

 families. 



The most important recent European writings on Palaeozoic Crinoids are 

 those of Mr. F. A. Bather of the British Museum, who has done much 

 valuable work in systematizing the terminology. His descriptive work has 

 been chiefly confined to the Fistulata of the Wenlock limestone of England, 

 and its equivalent in Sweden ; but we should like to see it extended to 

 include the Carboniferous Crinoids of England, of which careful study is 

 greatly needed. His admirable Monograph on the Crinoidea of Gotland, 

 Part I.,* arrived too late to be considered in this work as fully as would be 

 desirable ; in it, however, he has rendered a great service to all students by 

 bringing order out of the confusion in which the splendid Swedish collec- 

 tions had become involved by reason of Angelin's fictitious illustrations and 

 restorations. We hope nothing will occur to prevent the completion of 

 his work. 



* '' The Crinoidea Inadunata," with ten photographic plates, published by the Royal Swedish Academy 

 of Sciences. 



