HISTORICAL. 15 



Asterids. He also introduced a more rational terminology for the plates of 

 the caljX; which is still used by Zoologists and Palseontologists. He proposed 

 the name ^^ Basalia'' for the pelvis plates of Miller, and '' Radialia'' for Mil- 

 ler's scapulas and costals, including the first axillary. "When the rays are 

 free above the first radial, the axillary supports the arms ; but when that 

 plate forms a part of the calyx, it is followed by the " Distichalia'^' and these 

 by the ^' Palmaria'' For the supplementary plates he introduced the terms 

 '^ Interradialia^ Inter distichalia and Interpcdmariar 



Mliller divided the Crinoids into three great groups: the " Orinoidea Arti- 

 culata,^^ the " Orinoidea Tessellata " and the " Crinoidea Costata^^^ which he 

 defined, and of which he gave a list of the principal genera. 



Of the Articidata, to which Mliller referred Pentacrinus, Apiocrimis, Encrinus, 

 and the Comatulaa, he said that the rays develop directly from the base of the 

 calyx, and the lower ray plates are united laterally by a skin, which is either 

 naked or paved with irregular plates ; that this skin is -continued to the ven- 

 tral disk, closing the ventral side of calyx and arms; and that the radials 

 consist of three successive plates, of which the first and second, and the 

 axillary and the first arm-joint, are united by muscles. 



Miiller's Tessellata combine Miller's " Semiarticulata," and " Inarticu- 

 lata," and include the Blastoidea, Cystidea and the Cretaceous genus Mar- 

 supites. The calyx is composed of 3, 4 or 5 basals, which are sometimes 

 separated from the radials by a ring of " parabasals." Between the radials 

 there may be " interradials," and between the distichals and palmars, '^ in- 

 terdistichals/' and " interpalmars." The " Scheitel " (ventral disk) covers 

 the whole ventral surface ; it is constructed of solid plates, united at their 

 edges. 



The Tessellata were subdivided by Muller into two groups : Crinoidea 

 luith arms, and Crinoidea ivithout arms. To the former he referred all true 

 Crinoids and the Cystid genus Cari/ocrintis, forms having no separate anal 

 opening and no " Tentakelfurchen " (food grooves) upon the disk, and none 

 probably upon the arms. The armless Crinoids comprise the " Pentremites" 

 (Blastoidea) and " Sphaeronites " (Cystidea), forms with separate mouth 

 and anus. 



Miiller's classification, although a great advance upon that of Miller, was 

 not accepted by the French and English writers succeeding him ; but it was 

 revived later on by Ferd. Roemer and von Zittel. 



In 1842 a classification was proposed by Thos. Austin and Thos. Austin 



