THE 
CRINOIDEA CAMERATA OF NORTH AMERICA. 
INTRODUCTORY PART. 
I. HISTORICAL. 
Tue 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; Hntrochus to a series of joints, and 
Encrinus to the calyx of Enerinus liliformis, 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 Crimoids 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 Znerinus, 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 Pentacrinus 
caput-meduse 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 
* Mémoire sur les Encrinites et les pitrres étoilées, dans lequel on traitera aussi des Entroques. (Mém. 
de l Acad. Roy. Soc. de Paris, 1755 (published 1761), pp. 224-318. 
