.Plate XV. 



Echinocardium flavescens O. P. M. 



P. 26, 46. 



Fig. 172. A youiig speciraen, measuriug 1,7 mm., denuded of its spiiies; ventral view. The oesophagus lias 



already pierced the buccal membrane. 

 Fig. 173. The same; dorsal view. Tiie periproct, just formed, high up on the back. The fasciolre have begim 



to appear. In the frontal ambulacrum, III, a single pediocl, others beiiig pvobably löst. The 



details of the calycinal system were obscured by some opaque substance contained in the iiitostine, 



and could not be made out properly. 

 Fig. 174. The peristomal region of a specimen measuring 3 mm. 

 Fig. 175. A part of the peristomal region of a specimen between fig. 173 and 174. 

 Fig. 176. The top of a phyllodean pedicel in the early state, fig. 172. 

 Fig. 177. Another with two rods beginning to form. 

 F^ig. 178. The filaments with their rods a little more advanced. 

 Fig. 179. Another witii the psellion. 



Fig. 180. Another with the rudiments of three filaments. 

 Fig. 181. The disk of a phyllodean pedicel in a young specimen measuring 5,3 mm., with eight filaments in 



a circle and a ninth filament beginning an inner series. 

 Fig. 182. Spicules from its psellion. 

 Fig. 183. The peristomal part of an interradium from the inside, showing the transverse laminse, p. 26. 



