114 CATALOGUE OE THE BLASTOIDEA. 



Caryocrinus, with arras springing from the rim of the cup, was considered hy Say as a 

 Crinoid, intermediate between Ci/athocrinus and Actinocrimis. 



There can be no doubt, therefore, that Say considered the Blastoids to be a group 

 of Echinoderms of equivalent rank with Crinoids and Echinoids, and this is also the 

 view which we take of their zoological position. 



The group does not seem to have been definitely mentioned either by von Buch 

 or by Edward Forbes, though they both regarded the Cystids and Crinoids as separate 

 orders of Echinoderms, but ranked Caryocrinus with the latter, owing to its having 

 arms attached to the rim of the cup. Forbes l stated, however, that " the absence of 

 an ovarian pyramid is sufficient to show that the Pentremites are beyond the bounds 

 of the Cystidea3 ;" and he believed their position to be between this group and some 

 higher order of Echinodermata. 



The Cystidea were regarded by Volborth as true Crinoids on account of the arm- 

 like appendages which he found to occur in sonic of them. Roemer accepted this 

 view, and classed not only the Cystids but also the Blastoids as families of the order 

 Crinoidea, because of their pedunculate nature. He admitted, however 2 , with 

 respect to the Blastoids, that " obgleich ihnen freie Anne fehlen, so lassen sich doch 

 die rait Pinnuhe-ahnlichen Anhangen besetzten Fseudambulacral-Felder als mit der 

 Kelchschale verwachsene Arme betrachten, und diese entwickeln sich eben so vom 

 dorsalen Pole des Kdrpers aus, wie die Arme der eigentlichen Crinoiden." 



This step on Roemer's part has led to much confusion of terms, the word Crinoidea 

 having been variously used to designate only the truly brachiate forms for which 

 it was proposed by Miller, or as a comprehensive term for all the Stalked Echino- 

 derms. Miller's definition of the Crinoidea was an explicit one, and Say's "arms 

 none " still more so as regards the Blastoids ; while three years before the publication 

 of Roemer's monograph Leuckart 3 had proposed the " Pelmatozoa " as a class 

 embracing three orders, Crinoids, Blastoids, and Cystids. This fact seems to have 

 been unknown to Roemer 4 , even as late as 1852, when the ' Lethsea Geognostica ' 

 was published. He then raised the Blastoids from family rank to that of a suborder, 

 still keeping them, however, distinct from the Cystids ; and he regarded both groups 

 as equivalent in value to the truly brachiate Crinoids, which he proposed to call the 

 " Actinoidea." Bronn 5 , on the other hand, considered the Blastoids as a distinct 

 class of the " Strahlenthiere," for which he proposed the name " Blastactinota ; " 

 and he reinstated the Cystids among the brachiate Crinoids, with the class name 

 " Crinactinota." Burmeister ", a few years previously, had taken an opposite course 



' Mem. ((col. Survey Gfc. Brit. 1848, vol. ii. pt. 2, p. 528. 



2 Archiv f. Naturgesch. 1851, Jahrg. xvii. Bel. 1, p. 387. 



:t ' Ueber die Morphologic und die Yerwandtschaftsverhiiltnisse der Wirbellosen Thiero ' (Braunschweig, 

 1848), p. 42. 



* ' Lothsca Geognostica,' 1852, Bd. i. Th. 2, p. 224. 

 ' Die Klasscn und Ordnungen des Thier-Rcichs,' Bd. ii. 18G0, p. 180. 



' Zoonomiseho Briefe ' (Leipzig, 1850), Vol. i. p. 243. 



