Phylum Protoplasta [179 



In the growing plasmodium, a nucleus which is not dividing contains an endosome 

 ("nucleolus"). During mitosis, which occurs within the intact nuclear membrane, 

 the endosome becomes elongate, and a ring of chromatin, within which separate 

 chromosomes have not been distinguished, forms about its middle. The resulting "cru- 

 ciform" figure resembles some which have been seen in trypanosomes. The nuclear 

 divisions which occur immediately before cleavage are of a different character: no en- 

 dosome is seen, but there is a spindle with centrosomes at the poles, and definite 

 chromosomes are present. The occurrence of these two types of nuclear division has 

 been noted by every careful observer, Schwartz (1914), Home (1930), Cook (1933), 

 Ledingham (1939), and Karling (1944). Home was probably correct in supposing 

 the divisions which precede cleavage to be meiotic. Conjugation of the flagellate cells 

 of Spongospora has been observed. 



There are monographic accounts of the Phytomyxida by Cook ( 1933) and Karling 

 (1942). The group may be treated as a single family with a dozen genera and about 

 twenty-five species. 



Family Plasmodiophorea [Plasmodiophoreae] Berlese in Saccardo Sylloge 7 : 464 

 (1888). Family Plasmodiophoreen Zopf Pilzthiere 129 (1885). Family Plasmodio- 

 phoraceae Engler Syllab. 1 (1892). Family Woroninaceae Minden 1911. Families 

 Phytomyxidae and Woroninidae Poche in Arch Prot. 30: 198 (1913). Plasmodio- 

 phora, Polymyxa, Spongospora, and Sorosphaera attack land plants; Tetramyxa, 

 Ligniera, and Sorodiscus, chiefly aquatic seed plants; Woronina and Octomyxa, 

 Oomycetes; Phagomyxa, brown algae; Sporomyxa (Leger, 1908) and Mycetosporid- 

 ium, beetles. 



Class 3. RHSZOPODA Siebold 



Order Foraminiferes d' Orbigny in Ann. Sci. Nat. 7: 128, 245 (1826). 



Order Foraminifera Zborewski 1834. 



Rhizopodes Dujardin in Compt. Rend. 1: 338 (1835). 



Class Foraminifera d'Orbigny in de la Sagra Hist. Cuba vol. 8 (1839). 



Order Polythalamia Ehrenberg in Abh. Akad. Wiss. Berlin (1838) : table 1 ( 1839) . 



Class Rhizopoda and orders Monosomatia and Polysomata Siebold in Siebold 

 and Stannius Lehrb. vergl. Anat. 1 : 3, 11 (1848). 



Reticulosa Carpenter 1862. 



Stamm Rhizopoda and Class Acyttaria Haeckel Gen. Morph. 2: xxvii (1866). 



Thalamophora R. Hertwig Hist.Radiolar. 82 (1876). 



Class Reticidaria Lankester in Enc. Brit. ed. 9, 19: 845 (1885). 



Order Reticulosa Poche in Arch. Prot. 30: 203 (1913). 



Order Granuloreticulosa de Sacdeleer in Mem. Mus. Roy. Hist. Nat. Belgique 60: 

 7 (1934). 



Order Foraminiferida Hall Protozoology 250 (1953). 



Amoeboid organisms, the pseudopodia of the character of rhizopodia, i.e., fine, 

 freely branching and anastomosing; producing shells, these usually calcareous; com- 

 monly reaching macroscopic dimensions; mostly marine. 



The first examples of rhizopodes mentioned by Dujardin were milioles, vorticiales, 

 and le gromia: the genus Miliola is to be construed as the type. These organisms, the 

 proper rhizopods, are in general usage called Foraminifera, but that name was orig- 

 inally applied in the categoiy of orders. 



