Phylum Protoplasta [ 189 



Class 4. HEUOZOA Haeckel 



Family Polycystina Ehrenberg in Abh. Akad. Wiss. Berlin 1838: 128 (1839). 



Rhizopoda radiaria seu Radiolaria J. Miiller in Abh. Akad. Wiss. Berlin (1858) : 

 16 (1859). 



Echinocystida Claparede. 



Order Radiolaria Haeckel Radiolarien 243 (1862). 



Stamm Moneres for the most part, and classes Heliozoa and Radiolaria, Haeckel 

 Gen. Morph. 2: xxii, xxviii, xxix (1866). 



Subclasses Heliozoa and Radiolaria Biitschli in Brown Kl. u. Ord. Thierreichs 1, 1 

 Teil: Inhalt (1882). 



Class Proteomyxa Lankester in Enc. Brit. ed. 9, 19: 839 (1885). 



Subclasses Proteomyxiae, Heliozoariae, and Radiolariae Delage and Herouard 

 Traite Zool. 1: 66, 156, 169 (1896). 



Class Actinopoda Calkins Biol. Prot. 318 (1926). 



Class Actinopodea and orders Helioflagellida, Heliozoida, Radiolarida, and Proteo- 

 myxida HaU Protozoology 202, 203, 212, 220 (1953). 



Subphylum Actinopoda Grasse and Deflandre, and classes Acantharia, Radiolaria, 

 and Heliozoa Tregouboff in Grasse Traite Zool. 1, fasc. 2: 267, 270, 321, 437 

 (1953). 



Organisms having pseudopodia of the character of filopodia, stiffly radiating, or of 

 axopodia, stiffly radiating and having inner fibers; often with siliceous skeletons. 



Here, not without authority, one combines in one class the three groups which have 

 been treated as the classes Proteomyxa, Heliozoa, and Radiolaria; and adds further 

 two families of shelled amoebas. 



Cienkowski (1865) listed as "Monaden" the new species or genera Monas amyli, 

 Colpodella (apparently a chytrid), Pseudospora, and Vampyrella. They are minute 

 fresh-water amoeboid organisms, in part having flagellate stages. Haeckel (1866) 

 placed most of them (the Monas under the new generic name Protomonas), together 

 with his own discoveries Protamoeba and Protogenes, and also the bacteria, in his 

 Stamm Moneres, i.e., his group of Protista without nuclei. Later (1868) he omitted 

 the bacteria. Zopf (1885) found several of Haeckel's Moneres to possess nuclei, and 

 Lankester renamed the group Proteomyxa. Publication of subsequent original obser- 

 vations of these organisms has been scant and scattered; they remain poorly known. 



The Heliozoa as conventionally construed are also mostly inhabitants of fresh 

 water. Ehrenberg observed some of them and took them for Infusoria with immobile 

 cilia. There are only a few dozen species of Heliozoa sensu strict o (Schaudinn, 1896) : 

 the whole group is no more than a reasonable order. 



The Radiolaria (this name also used at this point in its conventional sense) are 

 marine. Examples were first observed as floating gelatinous bodies. These were taken 

 for fragments and remained unnamed until 1834, when Mayen named Physematium 

 and Sphaerozoum. Fossil skeletons of many examples were described by Ehrenberg 

 (1839). Huxley (1851) named Thalassicolla and gave an accurate account of its 

 structure. It was by work on organisms of this group that Haeckel first distinguished 

 himself (1862). 



Haeckel dealt further with this group in four important papers (1879, 1882, 1887, 

 1887-1888). In the last of these, the Radiolaria are a class of four legions, eight sub- 

 legions, twenty orders, 85 families, 739 genera, and more than four thousand species. 

 The categories, Haeckel explained, are purely relative: Radiolaria would as well be 



