Plaie XXII. 



Asterias pallida (Ag.). 



30. Portion of a radial section tln-ongli the raadrepovic intervadius of a star whose 

 E=2.5 nnu. xl53. 



31. Portion subjacent to the raadreporite, from a radial section of a star whose E— - 

 5 mm. X 153. 



32. A small portion of the section represented in fig. 40, to show the atrophy of the 

 protoproct. Stage intermediate between F and G. x 395. 



33. A small portion of a lateral wall of an arm of a star whose E=2.5 mm., to 

 show the origin of the peribranchial cavity. X 395. 



34. A small portion of a radial section of an arm next the terminal tentacle, of a 

 star whose E=5 mm. x 395. 



35. A portion of a horizontal section of the madreporic interradins of a star whose 

 E=2mm. x 153. 



36. Central portion of a star in stage H ; to show tlie formation of the metastome. 



x395. 



ABBREVIATIONS. 



an. pro protoproct. 



brach, d right brachiolarii arm. 



,, ijied median ,, ,, 



s left 



can. aq pore canal. 



can. aren stone canal. 



cav. perihœui perihœmal cavity. 



ent'c'l. a anterior euterocœl. 



,, cir circular ,, 



„ epigas epigastric „ 



„ p. d right posterior entei'occel. 



„ p. s left 



,, p'. s' secondai-y left posterior enterocœl. 



,, periœs periœsophageal enteroccel. 



gast stomach. 



int intestine. 



sin. ax axial sinus. 



sin', ax' closed portion of the axial sinus. 



tent. dor. a anterior dorsal tentacle ( = Ijipinnaria arm. 



„ „ p posterior „ „ 



„ med. a anterior median ,, 



„ ,, p posterior „ „ 



„ Ten. a anterior ventral „ 



„ ,, p posterior ,, „ 



vas. aq. cir circular water- vascular canal. 



„ „ rad radial ,, „ „ 



