CHROMIDIA AND THE BINUCLEARITY HYPOTHESES. 289 
Hertwig (’79) as a “ Kernrindenschicht” (text-fig. 5). Secon- 
dary nuclei (? gamete nuclei in all probability) are differen- 
TEXxT-FIG. 5. 
A radiolarian, Acanthochiasma krohnii, showing the re- 
markable cortical layer (** Kernrindenschicht,” Ks.) of the 
nucleus. This is probably the homologue of the chromidium 
of Thalamophora. (After R. Hertwig, ‘79.) 
TEXT-FIG. 6. 
Chromidia in a radiolarian—Thalassicolla. A, formation of 
isospores; B, of anisospores (probably gametes). In both 
cases the primary nucleus (N.) breaks up into chromidia, 
which give rise to secondary nuclei (v.) entering into the 
formation of the swarm-spores. In the formation of aniso- 
spores, a part of the nucleus remains behind (R.). The 
drawings are of the central capsule of the organism. (From 
Brandt, modified.) 
tiated from it in subsequent development, just as in Arcella, 
etc. (Hertwig, Porta). 
