PALEONTOLOGICAL GEOLOGY 
77 
would just leave that group for Springer to wrestle with, even if 
it took the latter twenty-five years. And sure enough, when his 
colleague who was then away returned, he gravely turned all the 
collection over to him for study and report. But Wachsmuth 
did not fully know his long time colleague and most intimate 
friend, nor his dogged perseverance. He little suspected in his life 
time that the odd, scragly little assemblage of fossils which he 
so readily spurned would in the course of a quarter of a century 
grow into a great company, the account of which would form a 
sumptuous enstallment equalling in every way the one which he 
had just helped to complete. 
Mr. Springer thus outlines his latest effort: “It is a fresh 
illustration of the growth of knowledge that the division of the 
Crinoidea which forms the subject of the present memoir was not 
known at all to the earlier systematic writers who treated of the 
Class; neither to J. S. Miller, with whose epoch-making mono¬ 
graph the systematic study of the crinoids as a group began nearly 
a century ago, nor to Johannes Mueller whose masterly researches 
upon the anatomy of the Echinoderms twenty years later, laid 
the foundations for future investigations upon their structure. 
The magnitude of the group as now understood is shown by the 
size of this treatise — and the progress above alluded to is further 
exemplified by the manner in which the subject has expanded 
under my hands. 
“When I began the study of Flexibilia, after the death of 
Wachsmuth, in 1896, it was part of a more ambitious plan to work 
up the two groups remaining after the Camerata; and of these it 
was supposed that the present group would be relatively a minor 
undertaking. I estimated that twenty-five plates would include 
all the necessary illustrations, and that these, with the text, would 
fall readily within the compass of a single volume. All the known 
material in this group in the museums of the world at that time 
did not occupy one-fourth of the space that is now required for 
the specimens of my own collection. 
Except for a few species, the Flexibilia are the rarest of all the 
fossil crinoids, some forms being represented by a single speci¬ 
men, and most of them by only a few. It was my early perception 
of the inadequacy of material, of the necessity of making further 
collections, and of examining as far as possible the types and other 
