20 
Dr. P. H. Carpenter on the 
distinguishes it accordingly as the cc Brachianal.” He states 
that u in size and position it is just like the adjacent arm- 
plate ” *. But is this really the case ? Is there tlie same 
articulation between its under surface and the bifurcating 
piece below it as between the latter and the arm-plate of the 
right posterior ray? This has yet to be demonstrated; and 
until such a demonstration has been given the term u axillary” 
should not be applied to the bifurcating piece, as has been 
done by Bather. Whatever be the merits of his theory, as 
applied to other Fistulata, there appear to me to be grave 
doubts respecting the correctness of his interpretation of the 
plate x in locrtnus. This is regarded by Wachsmuth and 
Springer as the first plate of the anal tube, and not in any 
way as a a special anal,” or brachianal as Bather calls it ; and 
if such be the case, the bifurcating piece on which it rests is 
not in any sense an axillary. Bather, however, not only calls 
it an axillary plate himself, but also represents the American 
authors and myself as having done the same, wdiich is not 
the case. I did not state “that Wachsmuth and Springer 
homologize the lower half of the compound radial in Dendro - 
crinus with the upper axillary plate in locrtnus .” Neither 
did the American authors misquote me u as having suggested 
that the axillary plate of locrtnus was an c azygos ’ plate ” f. 
Neither they nor I used the term “ axillary ” at all, so that 
there was no reason for Bather to represent us as having 
done so, more especially as we do not yet know that the plate 
in question is entitled to this name. 
6. Inter ambulacrals and Adambulacrals. 
In Muller’s classical memoir, “ Ueber den Bau der Echi- 
nodermen,” after discussing the views of de Blainville and 
A. Agassiz respecting the interambulacral plates of a Star- 
fish J, he proposed to distinguish the marginal plates of the 
ambulacra from the remaining interambulacral plates by the 
name “ adambulacral.” Those plates situated between the 
ambulacra on the ventral surface of the body, which are so 
w^ell developed in the pentagonal forms, w r ere called inter- 
mediary interambulacral plates ; and in a third category he 
placed the lower marginal plates of the rays. The term 
adambulacral proved to be a very convenient one, and it soon 
found its v r ay into the current nomenclature both of zoology 
and of palaeontology. It was not, however, adopted by A. 
* Ibid . p. 330. t Ibid. pp. 321, 322. 
t Abhandl. d. Berlin. Akad. Jahrg. 1853 (1854), pp. 161, 162. 
