Anatomical Nomenclature of Echinoder ms. 
19 
Illustrative Formulae . 
Ante don elegans A. R. 3. 2. (2) 
incequalis A. 3. 
(p). br b 
2 b 
porrecta A. 3. 2 j (p). br j . - 
Actinometra Solaris. ... a. R. 
paucicirra a. R. 
br ab 
2 * ab 
d. (p). br /a 
a, 
multibrachiata . . a. R. 3. ■ * ‘ ' ^ — — . 
2 a 
br be 
stelligera a. 2. 2. (2). 
2 
becomes A. c . 3. 2. (2) . ?. 
A Q (P)- ^ ?/ 
» O. . -. 
2 y 
„ A. 3. 2 | (p). h | . -i. 
c. b xy 
a. 
2 xy 
c. d. (p). b /X 
©■ 
c o P- p'.... p yi b y 
1/ O 
(l* — • O 
*■ 2 . 2 .( 2 ).* . £ 
2 xy 
5. The use of the term u Axillary T 
The term u axillary ” was introduced by Muller* and de- 
fined as follows : — u Das dritte radiale hat nach oben zwei 
dachfbrmig geneigte Gelenkflachen fiir die beiden darauf 
sitzenden Arme. Ich nenne es deswegen radiale axillare , es 
ist Miller’s Scapula , dagegen nenne ich hrachialia axillaria 
alle im Yerlauf der Arme vorkommenden ahnlichen Glieder, 
auf denen zwei Theilungsarme aufsitzen.” 
The term has been generally used in the Mullerian sense 
during the last forty years, i. e. only with reference to plates 
which serve as points of division in the rays and arms, 
whether these be free or incorporated into the more or less 
rigid dorsal cup. Bather, however, has recently extended its 
use in a manner which is scarcely advisable at present, since 
it is not as yet justified by anatomical research. He has 
applied the name to the u bifurcating piece ” in locrinus which 
gives rise both to the right posterior ray and to the ventral 
sac f. The lowest of the series of plates supporting the ven- 
tral sac— that which rests on the left upper edge of the bifur- 
cating piece, and is marked x in Bather’s diagram J— is 
regarded by him as having u originated as a plate morpho- 
logically corresponding to an ordinary brachial ; ” and he 
* “ Ueber den Bau des Pentacrinus caput Medusce” Abhandl. Berlin. 
Akad. 1841 [1843], p. 202. 
t Ann. & Mag. Nat. Hist. ser. 6, vol. v. 1890, p. 320. 
X Ibid. pi. xiv. fig. 5. 
2 * 
