THE RADIOLAR1A 



141 



disseminated through the endoplasm forming the centres about each 

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



'-gZg&^XMFg^ ' 



FIG. 24. 



Portion of a colony of Sphaerozonm 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 



C. 



B 



Fio. 25. 



A, formation of isos pores 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 uudif- 

 ferentiated nuclei and endoplasm ; b, 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 



