CLASS I CRINOIDEA 133 
as of equal value with the remaining orders. The divisions established by 
Wachsmuth and Springer are on the whole extremely well founded, and have 
been adopted as the basis of the following systematic arrangement. The term 
Inadunata is dropped, however, on raising the Larviformia and Fistulata to the 
rank of independent orders ; and for the terms Articulata and Canaliculata, the 
designations Flevibilia and Articulata are substituted respectively. 
[More recently an improved classification has been prepared by Wachsmuth and 
Springer, in connection with their as yet unpublished monograph on the Crinoidea 
Camerata of North America. The primary divisions of the Crinoidea as now recognised 
by these authors are shown in the subjoined table. 
Within the last few years, also, the terminology has been amended in several 
important respects; and conformably to the usage of the leading English and 
American authorities, certain of these changes have been adopted in the present 
edition. An explanatory note on the use of terms is therefore given at this place, in 
order to facilitate reference, and to exhibit the correspondence between the older 
terminology and the new. 
The only abbreviations employed in the text are the following :— 
IB =Infrabasals. Br=Brachials. 
B=Basals. RA =Radianal. 
R= Radials. IRA =F¥irst or special anal. 
In addition to these the following are used in the figures, but are printed in small 
letters :-— 
K=Calyx. O=Orals. 
Ar AM TISa TR=Interradials. 
St=Stem. Dist = Distichals. 
Explanation of Terms. 
Crown =Crinoid minus the stem. 
Calyx =Crinoid skeleton minus the stem and free arms. 
Dorsal cup= All parts of the calyx below the origin of the free arms. 
Tegmen=That part of the calyx lying above the origin of the free arms, and embracing the 
disk ambulacra, the mouth, and the anus. Includes the terms ventral disk, vault, dome, 
summit, ete. 
Base=That part of the dorsal cup lying next to the column. It may be composed of one or 
of two rings of plates, which are distinguished as basals and infrabasals. The basals adjoin 
the radials and alternate with them, being interradial in position. The infrabasals, when 
present, form the proximal ring, and are radially disposed. 
Radials=The circlet formed by the first plate in each of the rays ; or, the radially situated 
circlet of plates above basals, and this ring only. In some of the earlier Crinoids one or more 
of the radials are transversely bisected, in which case the two parts are distinguished as swper- 
radial and inferradial. (Abbreviated #} in the figures.) 
Brachials=A\l plates beyond the radials in radial succession. They are called jixed 
brachials so far as they take part in the calyx ; free brachials or arni-plates when they do not. 
The brachials forming the first circlet above the radials, whether free or fixed, are called 
primary brachials, or costa/s ; those of the second order distichals, or secondary brachials ; those 
of the third order pa/mars ; and all succeeding brachials, whether there are additional divisions 
in the ray or not, receive the name post-palmars. 
Interradials= All plates occupying the spaces between the rays proper, whether they belong 
to the dorsal cup or the ventral disk. Those of the dorsal cup, which are interposed between 
the brachials, are distinguished as interbrachials, and those of the tegmen, which lie between 
the ambulacra, as interambulacrals. 
Anals=Interradials of the posterior side, forming the base of the anal structure. The specia/ 
or first anal plate, when present, invariably rests upon the truncated upper face of the posterior 
basal, and between the radials. Higher anal plates may be present, even when the special 
anal is wanting ; they are interposed between the interbrachials following the median line of 
the posterior area. 
