THE RADIOLARIA 



concentrically. Imbedded in it are fatty and proteid reserves, 

 pigment, crystalline structures, and one or more nuclei. Oil- 

 globules are generally present in the Spumellaria and Nassellaria, 

 fatty granules in the Phaeodaria. The fat may be colourless or 

 coloured red, yellow, brown, or blue. The pigment is often 

 closely associated with the oil-globules, and occurs in Thalassophysa 

 on the peripheral surface of the globules. The crystalline 



Ph. 



f ,Arm 



fti?3& <?l&fe X '^A 



t\*S>r.. .'':; ''**-jyLi& s 



,FU>r. 



Portion of a section through Planktonetla atlantica, Borg., one of the Phaeodaria, to show 

 the phaeodium (Ph) tilling up the ectoplasm (Exo), x 80. (After Fowler.) Of. Fig. 29 for whole 

 animal. The black horizontal line is the "diaphragm" or ectocapsular membrane, that is 

 perforated by a single bundle of fibres (Fibr), if not also by the smaller similar structures (C). 

 In the upper ectoplasmic half of the figure the complex phaeodium is seen together with 

 branches (Sp) of the arms. In the lower half the delicate central capsule (C.c.) surrounds 

 thejendoplasm (End) and nucleus (Nu), and is itself enclosed in a shell (Sh) that forms a float. 



structures are of two kinds : (a) small whetstone -shaped bodies 

 probably of albuminous nature ; and (b) large rhombic structures 

 indestructible at a red heat. The latter, regarded by Brandt as 

 excretory, are in all probability crystals of strontium sulphate 

 (Biitschli). With this exception the contents of the endoplasm 

 may be regarded as reserve material destined partly for the 

 metabolism of the animal itself, but more especially for the 

 provisioning of the spores, into which the endoplasm breaks up. 

 Nucleus. The nucleus of the Eadiolaria is still very im- 



