THE RADIOLARIA 



149 



with six long radial spines. Phaeodium still in the primary shell. 

 Gazclletta, Fowler. 



C. Large forms, with conical shell, completely filled by central 



FIG. 28. 



Atlanlicdla cmspedota, 

 Bprgert. In this newly 

 discovered family of Phaeo 

 daria the central capsule 

 (C.c) is a large inflated 

 4 - lobate structure. The 

 skeleton consists of a me- 

 dian hollow part (M.Sk) and 

 of four pendent septate 

 arms (Sp). The black area 

 is the phaeodium (Ph). 

 X 50. (After Borgert.) 



Ph: 



capsule, which is converted into a swim-bladder. A diaphragm, perfor- 

 ated (Hacker [37]) by several astropyles and parapyles, separates 

 endoplasm from ectoplasm (Fig. 12). Phaeodium outside primary 



Fio. 29. 



Planktonetta atlantica, Borgert. 

 (After Fowler.) x 66. The entire 

 animal is shown as seen in a pre- 

 served specimen. One pair of arms 

 is omitted. The central capsule 

 (End) is invested by a skeletal 

 membrane and forms a float. The 

 arms are embedded in the phaeo- 

 dium (Ph) and attached to this 

 is the outer shell (f), comparable 

 with that of Medusetta and Atlanti- 

 cella. A section through this 

 animal is seen at Fig. 12, p. 120. 



End 



shell, with intra-phaeodial skeleton. A float present. Planktonetta 

 atlantica, Borg., Faroe Channel (29, 37). 



D. Large forms, without primary shell. Central capsule a swim- 

 bladder. Diaphragm and phaeodial skeleton as in preceding sub-family. 

 Secondary shell projecting over peristome. No float. Nationaletta. 



