366 



TYPES OF LARVAE. 



Of the larval forms included in the above list a certain 



en 



e.g. 



FlG. 21=1. TWO FREE STAGES IN THE DEVELOPMENT OF SYCANDRA RAPHANUS. 



(After Schultze. ) 



A. Amphiblastula stage. 



B. Stage after the ciliated cells have commenced to be invaginated. 



c.s. segmentation cavity; ec. granular epiblast cells; en. ciliated hypoblast cells. 



number are probably without affinities outside the group to 

 which they belong. This is the case with the larvae of the 



C 



FIG. 216. THREE LARVAL STAGES OF EUCOPE POLYSTYI.A. (After Kowalevsky.) 



A. Blastosphere stage with hypoblast spheres becoming budded into the central 

 cavity. 



B. Planula stage with solid hypoblast. 



C. I'lanula stage with a gastric cavity. 



</>. epiblast: hy. hypoblast; al. gastric cavity. 



