12 Dr. P. n. Carpenter on the 



axillary is the third plate above the basal ring. But whereas 

 Miiller would have described each type as having three radials, 

 Schultze said that this is only the case in Actinocrinus and 

 IlhodocrinuSj while Taococrinus and Zeacrinus have but one 

 radial followed by two brachials, of which the second is 

 axillary. In the first two parts of the ' Revision of the 

 Palgeocrinoidea ' Messrs. Wachsinuth and Springer used the 

 expression primary radials for the ray-plates in the body up 

 to the first axillary, i. e. the radials of Miiller, while the 

 following body -plates up to the next axillary (distichals of 

 Miiller) were called secondary radials, and so on, the term 

 " brachials " being used to denote " free radial plates sup- 

 porting the arms "''<■. At the same time, however, the 

 American authors suggested that the arms fundamentally 

 commence with the plates above the first radials, whether 

 these be free or incorporated into the calyx f ; and there are 

 many reasons for adopting this view, as I explained in the 

 Report on the * Challenger ' Crinoids \. In practice, how- 

 ever, Wachsmuth and Springer, like myself, found it more 

 convenient to regard the arms as beginning with the first free 

 plate beyond the calyx, and they described Encrinus as having 

 but one radial followed by two brachials, the second axillary 

 and bearing the arm -plates, which the older Avriters had 

 regarded as brachials following a series of three radials. 



In Zittel's ' Palaeontology ' § Schultze's views are adopted 

 and extended to the Neocrinoids, so that the calyx of Coma- 

 tula oxiiS. PentacrinuSf Encrinus axiiS. Mi'Uericrinus, is described 

 as having but one radial followed by two brachials. Ajno- 

 cri'nus, however, is said to have three radials, from which it 

 would appear that in Zittel's opinion the first articular facet 

 in this type is on the third or axillary radial. This, however, 

 is not the case, as was pointed out by myself in 1881 li, and 

 more recently again by dc Loriol ^. In any well-preserved 

 calyx of Ainocrinus which has the upper face of a first radial 

 exposed, a definite facet for a muscular articulation of the usual 

 character is plainly visible. This point is well shown in de 

 Loriol's figure of A. elegans*'^. There is a perforated trans- 

 verse ridge with muscular fossae above it and a dorsal fossa 



* Op. cit. part i. 1879, p. 27 (of separate copv). 

 t Ibid, pavtii. 1881, p. 10. 

 X Part i. pp. 47, 48. 

 § Oj). cit. ]). ooU. 



II " On two uew Crinoids from the Upper Chalk of Southern Sweden, "' 

 Quart. Journ. Geol. Soc. 1881, vol. xxxvii. p. 134. 

 11 Op. cit. p. 22o. 

 ** ()i>. cit. pi. xxxiii. li^s. 2 a, 2 I), pi. xxxiv. (i^s. Or/, l>. 



