22 THE CRINOIDEA CAMEEATA OF NORTH AMERICA. 



toids and many Cystids, the mouth was disconnected from the ambulacra; 

 and that in those Cystids in which more than one opening is represented, 

 the lateral one is the mouth, and not the central one, as had been generally 

 supposed. 



A different interpretation of the opening was given by Schultze, Sir 

 Wyville Thomson, Dr. W. B. Carpenter, Dr. Liitken, Loven and Wachs- 

 muth, who maintained that the mouth of all Echinoderms was located in 

 the centre of radiation, and insisted that the interambulacral opening was 

 the anus. Schultze * could not understand how a Crinoid with an interam- 

 bulacral mouth could be sufficiently provided with food, even if the arms 

 were prehensile organs, which they were not. He stated that Billings's im- 

 portant discovery, that the ambulacra enter the mouth by the arm openings, 

 left but little doubt that the mouth of the older Crinoids was subtegminal 

 and central ; that the food entered the body through the arm openings, and 

 was carried underneath the tegmen to a common oral centre. His views 

 were corroborated by Meek,t who saw Wachsmuth's famous specimen (PL 

 Y., fig. 10), and found the ambulacral tubes intact beneath the tegmen. 

 These observations were confirmed by Wachsmuth,J who had discovered 

 additional specimens with the ambulacra preserved, and most instructive 

 natural casts, in which the course of the ambulacra is indicated by ridges 

 upon the surface. 



In England, for a long time, very little attention was paid to the study 

 of fossil Crinoids, and many well known forms are undescribed to this day. 

 Among the earlier English writers were Mantell, Cumberland, Parkinson, 

 Phillips, McCoy, Sedgwick, and the Austins. Their descriptions in many 

 cases are so primitive that neither genera nor species can be identified. 

 They were followed by the writings of Rofe and Grenfell, and those of 

 Dr. P. H. Carpenter and F. A. Bather, whose excellent work attracted the 

 attention of every earnest student of Crinoids, and opened a new era in the 

 history of palseontological research. In France but little work was done 

 upon Palaeozoic Crinoids. Oehlert described a number of interesting De- 

 vonian forms, and among them several new genera. De Loriol, so well 

 known for his Monographs on the Crinoids of Switzerland and France, 

 directed his attention exclusively to Neozoic forms. 



* Monogr. Echinod. Eifl. Kalk., Wieii, 1867, p. 7- 



f Notes on some points in the Structare and Habits of the Palaeozoic Crinoideaj by F. B. Meek and 

 A. H. Worthen (Proc. Acad. Nat. Sci. Phila., 1869, p. 323). 

 X Amer. Journ. Sci. and Arts, Yol. XIV., August, 1877. 



