THE RADIOLARIA 



Fio. 31. 



Coelothamnus davidoffii, Btitschli ; one of the Phaeodaria. Entire animal drawn from a dead 

 specimen, x 4. Sixteen radii spring from the bivalve shell (S) which encloses the central 

 capsule. The ectoplasm (E) is shown investing the skeleton which supports it on the anchor- 

 like extremities of its tufted appendages. (After Btitschli.) 



Radiolaria (20-30 mm. in diara.). Selected forms: Coeloplegma 

 murrayanum, H. (Fig. 32) ; G. tritonis, H., Faroe Channel. 



As 



Fio. 32. 



Central capsule and adjacent structures of Codoplegma murrayanitm, H.; one of the Coelo- 

 graphidae. The bivalve shell (S) supports the hollow-branched galea (G), in which the phaeo- 

 dellae are seen emerging through the aperture (R) of the nasal tube (rhizocanna). The astropyle 

 (As) is drawn out into a tube. 



LITERATURE. 



1. Ehrenberg, Ch. G. Monatsberichte d. Berliner Akad. 1844-73. 



2. - - (Fossil Species.) Abhandl. d. k. Akad. Berlin, 1872, pp. 131-397. 



3. Huxley, T. H. (Thalassicolla.) Annals and Mag. Nat. Hist. vol. viii., 



1851, pp. 433-442. 



