REPORT OJT THE CRINOIDEA. 147 



Palasocrinoids the distal faces of tlie radials remain permanently in the horse-shoe 

 condition, and the ligaments and muscles must therefore have remained small and poorly 

 developed, just as they are in recent Crinoids until the central canal is completely closed 

 in. The gradual development of complete articular facets, commencing before the horse- 

 shoe stage, has been traced in the radials of the Palaeozoic Allagecrinus, just as in the 

 Comatulfe ■} and I see therefore no reason to doubt that many Palseocrinoids had an 

 imperfect articulation and not a suture between the horse-shoe facets of the first two 

 radials. This may perhaps be correlated with the small development of the arms of the 

 Palaeocrinoids, relatively to that of the calyx. The integrity of long arms with two 

 hundred or three hundred joints, like those of many Comatulae, would be much more 

 perfectly preserved if the bundles of muscles and ligaments were large and well developed 

 than if they remained small, as miist necessarily be the case on an imperfect terminal 

 facet of a semicircular or horse-shoe shape. 



Believing then that in a very large number of the Palseocrinoids the second radials 

 were at least as movable on the first as in Ajyiocrinus, and in some cases a good deal 

 more so, I cannot regard the " difi"erentia " of the Palaeozoic and the later Crinoids on 

 which MllUer and his followers laid so much stress, as a point of great systematic 

 importance. 



Wachsmuth^ omits all reference to the mode of union of the plates in his diagnosis 

 of the Palaeocrinoidea ; and had it not been revived by Zittel as a means of 

 distinguishing the two great groups, Muller's name would long ago have fallen into 

 disuse. 



The name Palaeocrinoidea was proposed by Wachsmuth^ in 1877 to denote "all true 

 Crinoids in which the actinal side is closed ; " but it was not actually defined by him 

 until two years later, nearly simultaneously with the appearance of Zittel's classification. 

 He regards the group as of sub-ordinal value, and as specially distinguished by two 

 characters — (l) the interradials constitute important elements of the test ; (2) the 

 absence of external food-grooves or oral aperture. He proposed incidentally to group the 

 later Crinoids together under the name " Stomatocrinoidea " ; but he did not attempt to 

 define the group ; and so far as I am aware, this name has not been adopted by 

 systematic zoologists, while Wachsmuth himself is now inclined to abandon it. Various 

 reasons, which will be explained more fully subsequently, have induced the writer to 

 propose the name of " Neocrinoidea " for the Mesozoic and later Crinoids. This has been 

 adopted by Prof. Zittel, and also by de Loriol in his work on the French Jurassic 

 Crinoids, and it will be used throughout these Eeports. 



Although Marsupites is ranked among the Tessellata by Miiller, and also, together 

 with Uintacrinus, by Schliiter and Zittel, I can see no reason for excluding these two 



1 Ann. and. Mag. Nat. Hist., 1881, ser. 5, vol. vii. pp. 283-287. « Revision, part i. p. 30. 



' Amer. Journ. Sci. and Arts, vol. xiv. p. 190. 



