190 THE VOYAGE OF H.M.S. CHALLENGER. 



Buch, however, clearl)^ distinguished the essential differences between Crinoids and Cystids.^ 

 The same was the case with Edward Forbes, who having given the Crinoids ordinal rank 

 in 1841^ under the remarkable name " Pinnigrada," assigned the same position to the 

 Cystids in 1848.' Von Buch seems to have considered the Blastoids as a third group of 

 equal value with these two. Roemer, on the other hand, degraded the Cystidea and 

 Blastoidea to the level of families or sections of the order Crinoidea, separating off the 

 brachiate forms of the latter as true Crinoidea.* A few years later he proposed to call 

 these by the name " Actinoidea," and to rank them together with Blastoids and Cystids 

 as suborders of the Crinoidea.'' This term was thus employed, not in the strict sense of 

 Miller's original definition, Ijut as co-extensive with the name " Pehnatozoa," which had 

 been proposed Ijy Leuckart four or five years previously ; though Roemer appears to 

 have been unacquainted with it. This was unfortunate, as the use of Leuckart's excellent 

 name in the Lethaea Geognostica would have avoided much subsequent confusion. 



In the second volume of Bronn's "Thier-Eeich " the Echinoderms aret hrowoi tooether 

 with the Coelenterates into the comprehensive " Kreis " of Strahlenthiere or Aktinozoa. 

 Four classes of Coelenterates are first considered, and then the Blastoidea and Crinoidea, 

 for which the cumbersome names " Blastactinota " and " Crinactinota " are proposed. 

 Fortunately, however, they have not come into general use. The Cystids are thrown 

 back among the Crinoids, for Bronn did not consider them as difi"ering from the brachiate 

 Crinoids to the same degree as the Blastoids. This was altogether in opposition to the 

 views of Von Buch and Edward Forbes, and also to those of Roemer," to whom the 

 peculiarities of the Blastoids and Cystids appeared so marked, " dass sie als gleichwerthige, 

 wenn auch nicht gleich umfangreiche Scctionen oder Unterordnuugen den iichten 

 Crinoiden entgegen zu setzeu sind." Viewed by the light of later knowledge, Bronn's 

 classification was of a distinctly retrogressive nature. 



Besides the Cystids he recognised two other divisions of the Crinoidea, viz., the 

 Brachiata or the Crinoidea proper, and the Costata, Miiller, the latter including the 

 problematical Saccosoma. 



The terminology employed by Bronn for the diflerent groups of the stalked Echino- 

 derms is extremely difficult to understand, and appears to contain many errors. Thus 

 on pp. 193 and 421 {op. cit.), the name "Actinoidea" for the true Crinoids is attributed 

 to Miiller, though it is really Roemer's, as explained above ; while on pp. 207 and 210 the 

 true Crinoids are referred to as " Anthodiata," in contradistinction to the other division 



1 Ueber Cystideen, Ahhandl. d. k. Akad. d. IViss. Berlin, 1845, pp. 12, 13, 17, 27. 



^ A History of British Starfishes and other Animals of the class Ecliinodei-mata, London, 1841, p. xiv. 



3 On the Cystidese of the Silurian Rocks of the British Islands, Mem. of ilw Geological Survey of Great Britain, and 

 of the Mmeam of Practical Geology, 1848, vol. ii. part 2, pp. 526, 527. 



* Monographie der fossilen Crinoiden-familie der Blastoideen, und der Gattung Pentatrematites im Besondern, 

 Archiv f. Naturgesch., Jahrg. xvii., Band i. pp. 387, 388. 



■■' Lethaea Geognostica, Bd. i., Theil 2, p. 224. 



" Op. cit., pp. 180, 193. ^ Lethaea Geognostica, Bd. i. Theil 2, p. 224. 



