CLASSIFICATION IOO, 



The earliest definite recognition of the taxonomic value of the funda- 

 mental structure upon which the present order Flexibilia is based was by 

 Wachsmuth in 1877, 1 when he proposed the name Taxocrinidae for one of the 

 three groups into which he thought the Paleozoic crinoids would fall. He 

 noted as its special characteristic the curved sutures between the plates of the 

 radial series, of which he said: "This .... is conspicuous in the radials, 

 thus producing apparently an articulate structure of the whole skeleton, and 

 indicating some degree of flexibility in the body as well as the arms." As to 

 the summit, or vault, which had not then been found preserved, he did not 

 think it consisted of a soft skin, but from fragments he had seen inferred that 

 the disk was covered by very small plates forming a " kind of scaly integument 

 which was pliant and flexible" (op. cit.. p. 185). Wachsmuth criticised 

 Roemer's course in including the Cyathocrinidae and Cupressocrinidae in his 

 section a, with vault consisting of a soft skin, he insisting that on the contrary 

 these two families belonged in a group by themselves having the vault covered 

 by an immovable arch of small plates. 



Angelin ~ in 1878 independently used the name Taxocrinidae as one of the 

 1 1 families under his section Trimera, placing the other Flexible crinoids un- 

 der the families Sagenocrinidae, Homalocrinidae and Ichthyocrinidae. He did 

 not propose any larger group for these forms, but divided the crinoids into 

 general sections founded upon the number of basals. 



Wachsmuth and Springer n in 1879 first treated the group systematically, 

 under the name Ichthyocrinidae (which they substituted for Wachsmuth's 

 Taxocrinidae), giving full diagnoses of the n genera then recognized, with 

 bibliographic lists of the species. The definition took note of the presence of 

 three " underbasals," and of the absence of pinnules, but emphasized as the 

 leading character the " peculiarity of structure which prevails throughout the 

 rays and arms . . . ," which " produces what seems to be an articulate structure 

 in the whole skeleton, and indicates that the body as well as the arms was 

 somewhat flexible" (p. 31). The pliant nature of the tegmen (vault) was 

 inferred from that of the dorsal parts, and from the indications observed in 

 fragmentary specimens. With rather inconsistent reasoning it was insisted 

 that the vault, although pliant, was composed of solid plates, this being a neces- 

 sary corollary of the assumption that all Paleozoic crinoids — then designated 

 as the Palaeocrinoidea — were distinguished from the Mesozoic and Recent 

 crinoids by having the " oral side closed by a more or less solid integument 

 without external food-grooves or oral aperture" (p. 30). It remained for 

 future years to bring forth the capital discovery, confirmatory of the inde- 



1 Amer. Jour. Sci., vol. 14, p. 185. 



2 Iconographica Crin. Sueciae, p. 8. 



3 Revision of the Palaeocrinoidea, pt. 1, p. 30. 



