II. TERMINOLOGY. 
Tue following terminology may be regarded as the result of a two years’ 
correspondence with the late Dr. P. H. Carpenter, carried on with a view 
to securing greater uniformity and precision in the morphological nomen- 
clature of the Crinoids; and we mutually agreed to adopt it in our future 
writings. On some points, Dr. Carpenter defined his own position in a paper 
which appeared about a year before his death.* 
Mr. F. A. Bather, in 1890, also t agreed to accept this terminology with 
very slight modifications, and applied it practically in his earlier descriptions 
of British fossil Crinoids, but renounced it in 1892,+ and proposed in its 
place a new one, which will be discussed later on. Many of the terms which 
are explained below are familiar to every student of Crinoids; but as some 
of them have been used in different senses by different authors, we include 
them for the sake of completeness. A few of them are new; others, though 
used by foreign authors, have never been introduced in American Crinoid 
literature. We believe that the terms are adapted equally well for the 
description of recent and fossil Crinoids, pinnulate as well as non-pinnulate. 
There are a few additional terms, not of such general application, which 
will be found explained in their proper places. 
The Crinoids, Blastoids and Cystids, with perhaps a few exceptions, 
differ from all other Echinoderms in being at some stage of their life pro- 
vided with a stem for attachment to other objects. This structure gives 
rise to a difference in habit, by which they live upon the aboral side, instead 
of creeping about mouth downward in search of food. 
The skeleton or test of a Crinoid consists of the stem or column, and the 
crown. If the stem is provided with lateral appendages, these are called 
cirri. Those of the distal end are the radicular cirri’, and form the root. 
The stem is constructed of the stem joints, of which the larger, and all cirrus- 
* “On some Points in the Anatomical Nomenclature of the Echinoderms ;” Ann. and Mag. Nat. Tist., 
1890 (July number). 
+ British Fossil Crinoids; ibid. (April number), pp. 806 to 330. : 
} Suggested Terms in Crinoid Morphology; ibid. (January), pp. 51-66 
