370 Scientific Intelligence. 



On pages 402-403 is described a remarkable case of ^ ' recupera- 

 tion," where a specimen of Taxocrinus colletti regenerated an 

 entire crown from the infrabasals and one basal, indicating that 

 ' 'the seat of vitality was lodged low down within the infrabasals. ' ' 



For twenty years. Springer has been gathering Crinoidea Flex- 

 ibilia and now he presents all the morphologic and geologic detail 

 of the 176 known species (54 new) in 31 genera (4 are new, but 

 Springer is the author of 13 } . Of these, 109 are American, the 

 remainder European. They begin in the Ordovieian with 2 

 forms, differentiate quickl}^ in the Silurian, where 71 are known, 

 34 occur in the Devonian, 68 in the Mississippian, and the order 

 dies out in the early Pennsjdvanian, where but a single species 

 is known. Besides, the author treats in the same detail 6 other 

 genera (Incertae sedis) that have been referred on insufficient 

 grounds to the Flexibilia, one of which is the curious Edriocrinus 

 with 9 species (4 new) that are attached by the calyx to foreign 

 objects, in this suggesting the recent Hoi op us. 



The author's principle of classification is morphologic and not 

 phylogenetic, and the order Flexibilia is said to be ''an offshoot 

 from the dicyelic Inadunata. . . through the non-pinnulate 

 Dendrocrinidae " (88) . This took place early in the middle Ordo- 

 vieian, in fact, it was at this time that most of the ordinal differen- 

 tiation of the crinoids from the c^^stids occurred. Springer says : 



"Thus it seems that at this very early stage in the geological 

 scale we have forms exhibiting variously intermingled characters 

 of the larger divisions of the crinoids, with some of the essential 

 cysticl structure more or less impressed upon one of them ; and 

 that these represent relatively recent departures from the common 

 ancestral type, tending in different degrees toward tlie lines 

 of evolution which produced the several orders of the crinoids. 

 In Protaxocrinus the Flexible characters were already well estab- 

 lished; in Cupullocrinus and Beteocrinus the tendency was 

 toward the Inadunata and Camerata respectively, while still com- 

 plicated by other characters; while in Cleiocrinus the strong 

 survival of cystid characters prevented the establishment of a 

 distinct evolutionary line in either of the crinoidal orders" (91). 



Springer maintains that with our present knowledge crinoids 

 are best classified into four orders, as follows: (1) Inadunata, 

 having generalized forms ranging from the Ordovieian to Recent ; 



(2) Flexibilia, having more or less specialized Paleozoic genera; 



(3) Camerata, with highly specialized forms; and (4) Articu- 

 lata, the latest derived crinoids, beginning in the Jurassic and 

 extending into Recent times. 



We congratulate Doctor Springer on the completion of this 

 monumental work, one of the best paleontologic monographs yet 

 published in America, and we look forward with much expecta- 

 tion to the several other works he announces. c. s. 



2. The Dunkard Series of Ohio; by C. R. Stauffer and C. R. 

 ScHROYER. Geol. Survey Ohio, 4th ser., Bull. 22, 167 pp., 13 pis.. 

 1 map, 1920. — In this very detailed account of the stratigraphy of 



