40 GENERAL ORGANIZATION OF THE PROTOZOA 



Typical genera: Ameba auct. Parameba, Schaudinn, 1S96; Trichospheriura, 

 Schneider; Hyalodiscus, Hert. and Lesser, 1874; Chromatella, Frenzel, 

 1892; Pelomyxa, Greeff, 1874; Dactylosphera, Hert. and Lesser, 1874; 

 Nucleophaga, Dangeard, 1895.^ 



Order 2. Testacea. The ameboid organisms here are covered by definite mem- 

 branes or tests composed of different materials cemented to a chitinous base. 

 The pseudopodia are protruded through the single opening of the shell and 

 may be simply lobose or branched, but do not anastomose. 



Typical genera: Arcella, Ehr., 1838; Cochliopodium, Hert. and Lesser, 1874; 

 Hyalospheria, Stein, 1857; Quadrula, F. E. Sch., 1875; Difflugia, Leclerc, 

 1815; Euglypha, Dujardin, 1841; Trinema, Dujardin, 1836; Campascus, 

 Leidy, 1877. 



Class 2. ACTINOPODA. Sarcodina provided with fine, ray-like pseudopodia 

 which are supported by a central axial filament corresponding to the kinetic 

 material of flagella. 



Subclass 1. Heliozoa. Typically fresh-water forms of actinate protozoa in which 

 there is no trace of a chitinous central capsule separating ectoplasm and 

 endoplasm. 



Order 1. Aphrothoraca. Naked forms of heliozoa (except during encystment). 



Typical genera: Actinophrys, Ehr., 1830; Myxastrum, Haeckel, 1870; Actino- 

 spherium, Stein, 1857; Actinolophus, F. E. Sch., 1874. 



Order 2. Chlamydophora. Heliozoa with a soft gelatinous or felted fibrous 



o^ 



Typical genera: Heterophrys, Archer, 1865; Spherastrum, Greeff, 1873. 



Order 3. Chalarathoraca. Heliozoa with a silicious covering made up of 

 separate or loosely connected spicules. 



Typical genera: Pompholyxophrys, Archer, 1869; Raphidiophrys, Archer, 1870; 

 Pinacocystis, Hert. and Lesser, 1874; Acanthocystis, Carter, 1863; Diplo- 

 cystis, Penard, 1890. 



Order 4. Desmothoraca. Heliozoa with a covering of one piece perforated by 

 numerous openings. 



Typical genus: Clathrulina, Cienk., 1867. 



Subclass 2. Radiolaxia. Actinopoda in which the inner protoplasm is separated 

 from the outer by a firm chitinous "central capsule" perforated in different 

 ways for the intercommunication of inner and outer parts. Exclusively salt- 

 water forms, living at the surface, suspended at various depths, or near the 

 bottom. Classification based upon Haeckel's magnificent monograph in the 

 Challenger reports. 



Division A. Porulosa. Spherical (homaxonic) organisms with spherical central 

 capsule perforated by numerous scattered pores of minute size. 



Legion 1. Peripylea (Spumellaria). The central capsule is perforated by evenly 

 scattered pores; a skeleton is usually present consisting of scattered silicious 

 spicules, fused spicules, or a latticed network. 



Order 1. Collida (following Brandt, 1902). Solitary forms with or without 

 skeletogenous spicules. 



Typical genera: Thalassicolla, Huxley, 1851; Actissa, Haeckel, 1887. 



Order 2. Spherozoea (Brandt). Colony building forms with or without skele- 

 togenous spicules. 



Typical genera: Collozoum, Haeckel, 1862; Collosphera, J. Miill, 1855. 



Order 3. Spheroida. Skeleton present as one or several concentric spherical 

 latticed or reticulate structures. 



1 In this group I would place, provisionally, the organisms of smallpox (Cytoryctes 

 variolse), of rabies (Neuroryctes hydrophobite), and the allied organisms wliich Prowazek 

 (1908) includes in his group Chlamydozoa. 



