THE METAMORPHOSIS OF ECHINODERMS., tos 
EXPLANATION OF PLATES 3—9, 
Illustrating Mr. Henry Bury’s paper ‘‘ On the Metamorphosis 
of Echinoderms.” 
REFERENCE LETTERS. 
Ant. B.C. Anterior body-cavity. 2.8.C. Right body-cavity. 2.B.C. Left 
body-cavity. Dors. Dorsal. Vent. Ventral. 2. Right side. JZ. Left side. 
W.V.R. Water-vascular ring. The numbers I—V mark the radii; the letters 
A—E mark the interradii. [In Figs. 3—9 the numbers I—V refer to the 
ciliated rings. ] 
Fic. 1.—Auricularia, seen from left side, showing process of left body- 
cavity running forwards to the hydrocel. x 75. 
Fic. 2.—The same; older specimen, in which the ciliated band is beginning 
to break up. x 75. (Hydroceel not quite correctly drawn). 
Fic. 3.—Auricularia, from ventral side. The skeleton and “ nerve-bands” 
are omitted, and the breaking up of the ciliated band is shown diagram- 
matically. x 75. 
Fic. 4.— Stage A” (transition of Auricularia to ‘‘ pupa”); from ventral 
side. 75. 
Fic, 5.—‘‘ Stage B”; from ventral side. x 75. 
Fic. 6.—Diagram of the anterior pole of Auricularia (compare Fig. 3), 
showing the breaking up of the ciliated band. 
Fic. 7.—Diagram of the anterior pole in stage A. 
Fic. 8.—Diagram of the anterior pole in stage B. 
Fig. 9.—Diagram of the anterior pole in young “pupa.” The gradual 
evolution of the ciliated rings can be followed with the help of the numbers 
and letters (I, Il a, 4, c, &c.), the former referring to the ciliated rings of the 
pupa,” and the latter to the parts of the ciliated band which form them. 
The references are the same in all the figures (3 to 9). 
Fie. 10.—Section of late Auricularia (between Figs. 3 and 4), showing 
position of polian vesicle, and extension of “ventral horn” of left body- 
cavity over to the right side. x 400. 
_ Fies. 11, 12, and 13.—Sections (from a series) through a larva towards the 
close of stage A, showing the extension of the “ventral horn” (‘part of 
L.B.C.”) of the left body-cavity round the cesophagus to the dorsal surface. 
Two other sections intervene between Figs. 11 and 12, and two between 
Figs. 12 and 18. Only parts of the sections are shown in the last two. x 
300. 
Fic. 14.—Diagram of the water-vascular system of the “pupa” seen from 
the dorsal (aboral) side. 
