12 
Dr. P. H. Carpenter on the 
axillary is the third plate above the basal ring. But whereas 
Muller would have described each type as having three radials, 
Schultze said that this is only the case in Actinocrinus and 
Rhodocrinus , while Taxocrinus 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 
Palaeocrinoidea 7 Messrs. Wachsmuth and Springer used the 
expression primary radials for the ray-plates in the body up 
to the first axillary, i. e. the radials of Muller, while the 
following body-plates up to the next axillary (distichals of 
Muller) were called secondary radials, and so on, the term 
u brachials ” being used to denote u free radial plates sup- 
porting the arms 77 * * § . 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 t ; and there are 
many reasons for adopting this view, as I explained in the 
Report on the ( Challenger 7 Crinoidsf. 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 writers had 
regarded as brachials following a series of three radials. 
In ZittePs c Palaeontology 7 § Schultze’s views are adopted 
and extended to the Neocrinoids, so that the calyx of Coma- 
tula and Pentacrinus , Encrinus and Millericrinus , is described 
as having but one radial followed by two brachials. Apio - 
crinus , 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 ||, and 
more recently again by de Loriol If. In any well-preserved 
calyx of Apiocrinus 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 
LorioPs figure of A. elegans **. There is a perforated trans- 
verse ridge with muscular fossse above it and a dorsal fossa 
* Op. cit. part i. 1879, p. 27 (of separate copy). 
t Ibid, partii. 1881, p. 10. 
% Part i. pp. 47 3 48. 
§ Op. cit. p. 339. 
|| u On two new Crinoids from the Upper Chalk of Southern Sweden,” 
Quart. Journ. Geol. Soc. 1881, vol. xxxyii. p. 134. 
% Op. cit. p. 225. 
** Op. cit. pi. xxxiii. figs. 2 a, 2 6, pi. xxxiv. figs. Ga, 6 b. 
