134 HENRY BURY. 
Fic. 15.—Longitudinal vertical section through “ pupa.” x 300. 
Fic. 16.—Section through the posterior end of the stomach in stage A, 
showing the extension of the right body-cavity on to the left side above 
(dorsal to) the stomach. The arrow marks the approximate position of the 
dorsal mesentery in preceding sections. Ectoderm and gelatinous tissue 
omitted. x 540. 
Fic. 17.—Lateral view (from left side) of a young larva of Asterias 
glacialis (?), showing constriction of left enteroccl into anterior body- 
cavity, hydroccel, and posterior body-cavity. Free-hand drawing. x 200 
(approximately). 
Fic. 18.—Ventral view of young “ Bipinnaria asterigera,” showing 
the terminal plates on the left of the middle line. x 35. 
Fie. 19.—Transverse section through Brachiolaria (Asterias rubens), 
showing dorsal organ underlying dorsal sac. xX 180. 
Fie. 20.—Transverse section through “ Bipinnaria asterigera,” show- — 
ing depression in centre of hydroccl. The position of one of the terminal 
plates is indicated (“terminal”), though the calcareous matter has been dis- 
solved away. xX 220. 
Fic. 21.—The same larva seen from the left side. The outlines of the 
body-cavities (dotted lines) have been filled in from sections, and are only 
approximate. From a decalcified specimen, somewhat shrunk. x 40. 
Fie. 22.—Dorsal view of a larva at about the same age. The dorsal me- 
sentery (not seen) runs just to the right of, and parallel to, the line of terminal 
plates (compare Fig. 20). x 70. 
Fic. 23.—Transverse section of a very old specimen of “ Bipinnaria 
asterigera.” 55. 
Fic. 24.—View from the left side of the same larva (oral side of adult), 
reconstructed from sections. The interradial septum dividing the “‘axial sus” 
from the left body-cavity is shown; the other four are omitted. 
Fic. 25.—Section of the same larva, through two of the radial pouches of 
the stomach. x 75. 
Fic. 26.—Transverse section through an arm of young Lindia, showing the 
hepatic ceca. xX 40. 
Fic. 27.—Ventral view of young larva of Asterias glacialis (?), showing 
the left body-cavity passing on the dorsal side of the intestine on to the right 
side. x 100. 
Fie. 28.—Transverse section through a larva of Asterias rubens at 
about the same stage as the last. x 300. 
Fic. 29.—Transverse section through a young pluteus of Echinus micro- 
tuberculatus, showing the “dorsal sac.’ x 440. 
Fic. 30.—Transverse section through a later pluteus of the same, showing 
the raised floor of the “dorsal sac.’ x 900. 
Fie. 31.—Longitudinal vertical section of the same. x 900. 
