(unipolar growth). 149. _The Ontogeny of the Phæodaria._--The individual development of the PHÆODARIA in the simplest case stops with the skeletonless condition of the Phæodinida (_Phæodina_, _Phæocolla_), which can be immediately derived from the foregoing _Actissa_-stage by the disappearance of the pores in the greater part of the central capsule, the characteristic astropyle being developed at the basal pole (§ 60). Since this particular form and structure of the spheroidal central capsule remains the same in all PHÆODARIA, whilst the formation of their skeleton follows very different directions, it follows that further common paths of development are excluded both ontogenetically and phylogenetically. What will be laid down in this respect as regards the phylogeny of the different groups of PHÆODARIA (§§ 194-199) holds true also of their ontogeny. The relations of growth in the three dimensive axes are hence very different in the skeletons of the various groups of PHÆODARIA. This difference is best marked in the #Phæoconchia#, whose bivalved lattice-shells have as their ground-form the rhomboid pyramid of Ctenophora. In most #Phæogromia# the monaxon lattice-shell may develop simultaneously by sudden excretion at a particular moment of lorication; this is also the case with the polyaxon lattice-shells of the #Phæosphæria#. In their future growth the development of basal or radial apophyses is of special importance. In the majority of the PHÆODARIA these apophyses are tubes of silicate filled with jelly (often provided with an axial siliceous thread); thus their development is distinguished by complications which are absent in the case of the other three legions.