Besides these genera enumerated by Schaudinn, we include Dimorpha Gruber (Fig. 37 5, p. [112]), Mastigophrys Frenzel, Ciliophrys Cienk., and Actinomonas usually referred to Flagellates.
K. Brandt, in Arch. Prot. i. 1902, p. 59, regards the presence of spicules as not even of generic moment, and subdivides the Collodaria into two families—Collida (solitary), and Sphaerozoea, colonial, i.e. with numerous central capsules.
Dreyer adds an additional order—Sphaeropylida, distinguished by a basal (or a basal and an apical) pylome.
Verworn has shown that Thalassicolla nucleata can, when the exoplasm is removed from the central capsule, regenerate it completely. First a delicate exoplasm gives off numerous fine radiating pseudopodia, and the jelly is re-formed at their bases, and carries them farther out from the central capsule. See General Physiology (Engl. ed. 1899), p. 379.
The pigment is singularly resistant and insoluble, and shows no proteid reaction. Borgert states that it appears to be formed in the oral part of the endoplasm, and to pass through the astropyle into the ectoplasm, where it accumulates. It is probably a product of excretion, and may serve, by its retention, indirectly to augment the surface. See Borgert, "Ueb. die Fortpflanzung der tripyleen Radiolarien" in Zool. Jahrb. Anat. xiv. 1900, p. 203.