The luminous genus, Pyrocystis (Fig. 47), regarded as a Cystoflagellate by Wyville Thomson, has a cellulose wall, no mouth, and in the zoospore state has the two flagella in longitudinal and transverse grooves of the Dinoflagellata.
This process has the character of telolecithal segmentation in a Metazoan egg.
See Doflein, in Zool. Jahrb. Anat. xiv. 1900, p. 1.
London, 1753, 402-403.
On this account Hickson has termed the group "Heterokaryota" in Lankester's Treat. Zool. i. fasc. 1, 1903.