THE 



CEINOIDEA CAMERATA OF NORTH AMERICA. 



INTEODUCTORY PART. 



I. HISTOEICAL. 



The first reference to Fossil Crinoids, according to De Koninck, was 

 made by Agricola in the second half of the sixteenth century. He distin- 

 guished between Trochites, Entrochus, and Encrinus. The former name he 

 applied to all detached stem-joints; Entrochus to a series of joints, and 

 Encrimis to the calyx of Encrinus liliiformis, at that time the only Crinoid 

 in which a crown had been found in connection with the stem. As early 

 as the seventeenth and eighteenth centuries the crinoidal remains received 

 the attention of a large number of writers, some of whom regarded them as 

 plants, others as animals. 



Rosinus, who lived at the beginning of the eighteenth century, was the 

 first writer to show that the Crinoids were not plants, as before then gene- 

 rally supposed, but were closely related to the Asterids, and especially to 

 the group which afterwards received the name Euryale. He also supposed 

 that the Trochites and Entrochites were parts of Encrinus, and not inde- 

 pendent bodies. 



An important advance in the knowledge of the Crinoids was made by 

 Guettard,* who described the first recent Stalked Crinoid that ever came to 

 Europe. He gave this species, which was afterwards known as Pentacrimis 

 cajput-medusce Lamk., the popular name '^Palmier marin," and took it to be 

 the type of all fossil Crinoids with pentagonal stem, as opposed to those 

 with a round stem, of which he thought the living type had not been dis- 

 covered. He gave a moderately fair description of its structure ; but added 



* Memoire sur les Encrinites et les pierres etoilees, dans lequel on traitera aussi des Entroques. (Mem, 

 de I'Acad. Roy. Soc. de Paris, 1755 (published 1761), pp. 224-318. 



