THE RADIOLAR1A 



141 



disseminated through the endoplasm forming the centres about each 

 of which a crystal, an oil -vesicle, a vacuole, and granule are 



Fio. 24. 



Portion of a colony of Sphaerozoum neapolitanum about to form isospores. The spicules and 

 "yellow cells" are omitted. The central capsule has disappeared, and only a thin peripheral 

 ectoplasmic layer is present. Minute crystals are scattered through the endoplasm, and two- 

 oil-globules (o) are shown. X 300. (After Brandt.) 



clustered. The whole endoplasm is now transformed into a mass 

 of biflagellated spores. The central capsule suddenly disappears,, 

 and the ectoplasm, which in the interval has undergone contraction 



ci 



B 



Fio. 25. 



A, formation of isospores in Collozoum inerme. Two stages are shown on opposite sides of 

 a central capsule. On the left side the nuclei and crystals are aggregated peripherally, but the 

 central oil-globule is intact. On the right the nuclei are smaller and more numerous and the 

 oil-globule is breaking down. B, formation of heterospores in the same shown by quadrants, 

 a, early stage ; several grouped, modified nuclei and fat-granules ; between the groups are undif- 

 ferentiated nuclei and endoplasm ; 6, c, and d are later stages. 



and degeneration, breaks to pieces. The colony descends and the- 

 isospores swarm out, leaving (in the Collosphaeridae) the large 

 crystals and the greater part of the pigment behind. Each is a- 



