Geology, 369 



as a whole is to be commended as one which not only the student 

 bnt any reader would be glad. to possess. f. e. b. 



II. Geology. 



1. The Crinoidea FlexihUia; by Frank Springer. Smith- 

 sonian Institution Pub. No. 2501, two vols., text and plates, 486 

 pp., 79 pis., 51 text figs., 1920. — In these two grand volumes we 

 have the results of a long labor of love by an able lawyer, a work 

 made possible largely through his own financial resources and 

 paleontologic ability j"^ though he works at Washington in a most 

 stimulating environment and in an institution that will always 

 fully appreciate the gift of his great collections. The printing 

 and paper of the monograph are of the best and the heliotype 

 plates well reproduce the very beautiful and accurate drawings of 

 Mr. Greorg Liljevall, of Stockholm, and Mr. K. M. Chapman, of 

 Sante Fe. 



Wherever crinoids occur, there the author, or others for him, 

 have gone and labored long to get these usually rare fossils. 

 These co-workers he loves as much as his adopted children, the 

 Echinoderma, and on pages 8 to 15 and in places throughout the 

 text he writes feelingly and interestingly of their help and talent. 

 The volumes are dedicated to the man who started him on his 

 career in paleontology, Charles Wachsmuth, '^ collaborator and 

 friend of early years. ' ' 



It is interesting to note that the Silurian of Decatur County, 

 western Tennessee, has yielded as great a variety of crinoids as 

 that of the Swedish island of Gotland, and that they exhibit ^'in 

 some respects a remarkable parallelism with the Gotland fauna, ' ' 

 while the Laurel limestone of Indiana bears a similar striking 

 resemblance (p. 15). Both American areas got their faunas 

 through what is now the Gulf of Mexico embayment. 



While the author 's method of study is in the main morphologic, 

 yet the fossil forms are also studied in the light of the recent 

 crinoids. He tells us that of living forms there are now described 

 567, with about 50 new ones to be defined, and that the U. S. 

 National Museum has no fewer than about 350 species represented 

 by 5,387 specimens. This great collection of recent crinoids has 

 been built up largely by Doctor Austin H. Clark, with the back- 

 ing of Mr. Springer. Close attention is also given to the onto- 

 genetic stages in living genera, and many of these stages (in 5 

 genera) are figured from drawings by H. E. Wilson on the three 

 first plates. ' In Comactinia meridionalis from off Yucatan there 

 is retained a longer series of development stages than is commonly 

 present, and the study of this species leads the author to conclude 

 that there is "in the ontogeny of this living crinoicl an unusually 

 close recapitulation of the phylogenetic history of some of the 

 Paleozoic groups of the class" (86). The Taxocrinidae "repre- 

 sent the true Flexibilia type, ' ' and are ' ' comparable to stages in 

 the ontogeny of living crinoids" (96). 



