570 



CRINOID LARVA. 



depression corresponding in position with the now closed blas- 

 topore (vide p. 550). The third ciliated band bends forward 

 to pass in front of this (fig. 269). Behind the last ciliated band 

 there is present a small depression of unknown function, also 



FIG. 268. THREE STAGES IN THE DEVELOPMENT OF ANTEDON (COMATULA.) 



(From I.ubbock; after Thomson.) 



A. larva just hatched; B. larva with rudiment of the calcareous plates; C. Penta- 

 crinoid larva. 



