CLASS i CRINOIDEA 133 



as of equal value with the remaining orders. The divisions established by 

 Wachsniiith and Springer are on the whole extremely well founded, and have 

 been adopted as the basis of the following systematic arrangement. The term 

 Inuiliiinitn is dropped, however, on raising the Larrifnrinm and Fistulata to the 

 rank of independent orders ; and for the terms Articulata and Canaliculatn, the 

 designations Flexibilia and Arlii-nlnttt are substituted respectively. 



[More recently an improved classification has been prepared by Wachsmuth and 

 Sprin-.-r, in connection with their as yet unpublished monograph on the Crinoidea 

 ( 'um.-rata of North America. The primary divisions of the Crinoidea as now recognised 

 by these authors are shown in the subjoined table. 



Within tin- last few years, also, the terminology has been amended in several 

 important respects ; and conformably to the usage of the leading English and 

 Ameriran authorities, certain of these changes have been adopted in the present 

 r.lition. Aii 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. 



= Basals. RA = lUdianal. 



fi = Radials. IRA = First or special anal. 



In addition to these the following are used in the figures, but are printed in small 

 letters : 



K= Calyx. = Orals. 



IR = Interradials. 



Explanation of Terms. 



= Crinoid minus the stem. 

 /' = Crinoid skeleton minus the stem and free arms. 

 ' ,-i/ji- All parts of the calyx below the origin of the free arms. 



n 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, 

 in a i HI it, etc. 



-Z?ose = Tliat 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 infrctbasals. The basals adjoin 

 the radials and alternate with them, being interradial in position. The infrabasals, when 



t, form the proximal ring, and are radially disposed. 



A',////,//.-,- = 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 super - 

 inferradial. (Abbreviated Ji 1 in the figures.) 



ilx All plates beyond the radials in radial succession. They are called faced 

 brachials so far as they take part in the calyx ; free brachials or arm-plates when they do not. 

 The brachials forming the first circlet above the radials, whether free or fixed, are called 

 //////////// hrachials, or cost(ils_ ; those of the second order distichals, or secondary brachials ; those 

 of the third order pal mars ; and all succeeding brachials, whether there are additional divisions 

 in the ray or not, receive the name post-palmars. 



/i/f< r/adials = 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 special 

 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. 



