IX] 



OF THE RADIOLARIAN SKELETON 



469 



extremely common, and among its many variants may be found 

 cases in which (e.g. Actinomma), the vesicles have been less 



Fig. 221. Aulonia hexagoim, Hkl. 



Fig 222. Actinomma arcadophorum, Hkl. 



regular in size, and some in which the hexagonal meshwork has 

 been developed not only on one outer surface, but at successive 



