HISTOEICAL. 13 



to be struck by the resemblance they bear to the crown of Pentacrinus, and 

 he pointed out that the pentagonal plate at the base of the subglobose body 

 of the ComatuIsB occupies the position of the first column joint of the 

 " Crinoidea." 



Miller subdivided the Crinoidea into four groups : the Articulata, to 

 which he referred the genera " Apiocrinites, Encrinites and Pentacriniies ;'' the 

 Semiarticulata with " PoteriocrifiUes;'' the Inarticulata wiWi " Ci/athocrl 

 nites, AcUnocriniteSj Bhodocrinites, and Platycrinites ; " and the Coadunata with 

 '' EugeniaerinUes'' His primary groups were based upon the mode of union 

 between the stem and calyx, and between the latter and the arms; his 

 genera upon the number and arrangement of the plates in the dorsal cup. 

 Considering that in 1821 only about twenty-five species of Stalked Crinoids, 

 recent and fossil, were known, and many of them only from fragmentary 

 specimens, we cannot help admiring the genius of Miller, who brought 

 order out of chaos, and laid the foundation of the present classification of 

 the Crinoidea. His genera have been generally accepted, and are now rec- 

 ognized as the types of well-marked families. 



Miller introduced an elaborate terminology, but unfortunately did not 

 always apply his terms to the same parts. In some of his genera he gave 

 the term "pelvis" to the proximal ring of the plates within the calyx, in 

 others to the plates of the ring above. In Apiocrinus and Actinocrinus he 

 called the radials "first costals;" the succeeding ones "second costals," and 

 the first axillaries " scapulaB." In Platycrimis^ however, and in Poteriocriniis 

 and Cyathocrinns, the radials are his scapulae, and are followed by arm plates. 

 Platycriniis^ according to Miller, has no costals at all ; but in the dicyclic 

 Cyathocriniis and Poteriocriniis costals are said to be represented by the plates 

 of the interradial basal ring. 



A year after the appearance of Miller's work, Schlotheim published the 

 first part of the Supplement to his Petrefactenkunde,^ reproducing therein 

 Miller's figures together with his own, and adopting his generic and specific 

 names. A year later, however, in the second part of that work, he withdrew 

 Miller's generic names, and referred all Stalked Crinoids back to EncrimiB and 

 Pentacrinus respectively. 



Goldfuss in his great workf adopted Miller's classification and termi- 

 nology. Cumberland t did not consider Miller's name " Crinoidea " appro- 



* Nachtrage zur Petrefactenkunde, 1822-1823 (3 Bande, mit 37 Kupfer-Platten). 

 t Petrefacta Germaniae, Dusseldorf, 1826-1833. 

 X Reliquiae conservatse, Bristol, 1826. 



