Review of Recent Geological Literature. 259 
comes a new and ponderous monograph containing a mine of suggest- 
ive information, exhaustively considered and superbly illustrated. 
The great feature of general interest is the bearing of the discus- 
sion on crinoid classification. At a single stroke all existing classifi- 
cations are not only thrown into confusion, but the last prop is taken 
from under certain of those schemes of systematic arrangement which 
are claimed to rest securely on phylogenetic foundations. 
Uintacrinus has long been regarded as one of the rarities in crinoid 
collections. Its recorded occurrences were few. Mr. Bather, however, 
after wide travel in Europe, found the form to be really widely and 
abundantly distributed. In Kansas, great slabs containing hundreds of 
beautifully preserved specimens were recently obtained. 
To the morphologist, Mr. Springer's studies are a revelation in 
many ways. Some features which he brings out are unique. The re- 
markable information relating to the structure of the base is particularly 
noteworthy. The main distinguishing feature of the two great sub- 
classes of Dicyclica and Monocyclica are here found in one and the 
same species. 
In order to appreciate fully the importance of the present discovery, 
reference must be made to the recent text-books on zoology and paleon- 
tology. "There is no doubt that the occurrence of these two forms of 
base in this genus is a most extraordinary fact. Nothing like it has 
ever been observed before among the crinoids, to my knowledge." says 
Mr. Springer. "Wachsmuth and Springer held the presence or ab- 
sence of infrabasals to be a good family character, except in case of 
the Reteocrinidae, in which dicyclic and monocyclic genera — otherwise 
markedly similar — were included by us. It was the difficulty presented 
by these genera that prevented us from attributing to this character a 
higher value and wider significance. Mr. Bather, on the other hand, 
considered the difference in the two forms of base as sufficient to sep- 
arate the Crinoidea Inadunata into two suborders. He has lately in 
the chapters on the-Echinodermata in Part III of Ray Lankester's treat- 
ise on zoology, elaborated a scheme of classification, embracing the 
whole of the Pelmatozoa, on phylogenetic principles, in which he sub- 
divides the class Crinoidea into two sub-classes : Monocyclia and Di- 
cyclica. 
"The validity of such a division of the Inadunata was first combated 
and denied in the monograph of the Crinoidea Camerata, upon grounds 
which it is not necessary to restate here. There was undoubtedly much 
plausibility in the suggestion of these two divisions, more as to the 
Inadunata than to the Camerata. What made it especially attractive 
was the fact that it was based upon differences in the primitive ele- 
ments of the crinoid organization, representing phylogenetically dift'er- 
ent early stages of the only crinoid whose embryology we know. And 
the argument which was considered by its author to be conclusive, was 
the assumed fact that there was no such thing as a transition from one 
form of base to the other. What, then, is the significance of the pres- 
ent discovery in relation to this question? It presents a difficulty far 
more formidable than the case of the ReteorcrinidK. 
