138 THE CRINOIDEA 



THE CLASSIFICATION OP THE CRINOIDEA. 



When the modifications above described have been grasped, when it 

 is remembered that these are only the more usual among the changes 

 that take place, and that there are others even more remarkable, and 

 when it is learned that most of these may affect members of any group 

 at any period, then it will be understood that the decipherment of the 

 few and fragmentary leaves of crinoid history that have been preserved 

 to us has been a long and difficult task, full of vain attempt and 

 rejected theory, and that classification after classification has been raised 

 but to fall ; and still the leading writers cannot agree, even provisionally. 



An admirable account of the literature on this class, from Agricola,' 

 in 1558, to C. F. Koemer, in 1853, was given by de Koninck and Lc 

 Hon (1854), and supplemented by W. B. Carpenter (1866). The 

 nomenclature of genera and species dates, of course, from 1758, the year 

 of publication of the tenth edition of Linnaeus's Systema Naturae; but 

 neither Linnaeus nor his immediate successors were more happy in their 

 dealings with this then little known group than more ancient authors. 

 It was J. S. Miller of Dantzig and Bristol, who, in 1821, laid the 

 foundation for a scientific knowledge and classification of the CRINOIDEA, 

 as he was the first to name them. Accounts of the subsequent growth of 

 knowledge and theory are so accessible in Zittel (1879, 1899), .P. H. 

 Carpenter (1884), and Wachsmuth and Springer (1897), that only the 

 main stages need recalling, and that briefly. 



Miller's CRINOIDEA excludes unstalked genera ; the others known to 

 him are divided into : ARTICULATA : ossicula forming the cup articula- 

 ting, Apiocrinus, Pentacrinus, Encrinus. SEMI- ARTICULATA : plates of cup 

 articulating imperfectly, Poteriocrinus. INARTICULATA : plates adhering by 

 sutures, lined by muscular integument, Cyathocrinus, Actinocrinus, Rhodo- 

 crinus, Platycrinus. COADUNATA : proximal ossicles of cup anchylosed to 

 proximal columnal, Eiiyeniacrinus. The principles of classification here 

 adopted profoundly influenced subsequent attempts, while the genera 

 form the types of modern families. 



Joh. Miiller (1843) meant by "Crinoidea" all Pelmatozoa, dis- 

 tinguishing the crinoids proper as Crinoidea, brachiata. Among these 

 he retained Miller's ARTICULATA, adding to it the Antedonidae, and 

 stating that the rays developed from the base of the cup, and merged 

 into the free arms ; that the proximal plates of the rays were laterally 

 united by an integument continuous with that of the ventral surface ; 

 that the radial and first primibrach, the primaxil and first secundi- 

 brach, were joined by muscles, but the first and second primibrachs by 

 muscles or syzygy ; and that food -grooves, mouth, and anus were 

 visible on the tegmen. The peculiar genus Saccocoma, unknown 

 to Miller, was made the type of the COSTATA : stemless, without centro- 

 dorsal, and with processes from the brachials (pinnulae oppositae, Miiller). 

 Haplocrinus mespiliformis was separated under the head TESTACEA : cup 

 and tegmen forming a firm, connected test, with five ambulacra running 

 up to the mouth. Holopus was regarded as an entirely independent and 

 peculiar division of the Crinoidea (sensu lato), on account of its sessile cup 



