SPECIAL MORPHOLOGY AND TAXONOMY OF SARCODINA 341 



pseudopodia are blunt at the base but provided with long sharp 

 points. 



Sub-family Nebelinoe.—Jiere the tests are transparent and dome- 

 shaped except for lateral compression. They are homogeneous and 

 transparent in Hyalosphenia but are covered with scales, plates, 

 etc. in other genera. A definite thickening of the shell about the 

 aperture is typical of Awerintzia. In Ileleopera the crown of the 

 test has a few sand grains adherent, while in Nehela and Quadrula 

 the test has an outer covering of scales which are quarlrangular and 

 arranged in oblique rows in Quadrula, and are circular, oval or 

 irregular in Nehela. 



Sub-family PseudonebelinoB.—Here the test is usually flexible 

 either in the region of the aperture only, as in Ainpkizonella, or 

 throughout as in Zonomyxa (which is multinucleate) and Cochlio- 

 podiuin (uninucleate). In Leptochlamys only, is the test rigid, 

 structureless, and transparent, and with a peculiar ball-like single 

 pseudopodium. 



Family 2. Euglyphidae. — In members of this family the test is 

 covered by silicious plates or scales and the pseudopodia are of a 

 filose, branching type. The tests may be either symmetrical or 

 asymmetrical. In the former group the aperture is terminal, cir- 

 cular and provided with teeth in Euc/lypha formed from scales; 

 or the eflge of the aperture is smooth or slightly serrated in Sphe7io- 

 deria. In asymmetrical forms the mouth is subterminal, and 

 oblique in Campascus. The test is retort-shape in CypJioderia, 

 Campascus and Nadinella. It is pyriform but much compressed in 

 Plarocisfa (without toothed membrane) and Assulina (with toothed 

 membrane about the aperture). In Paulinella the test is Euglypha- 

 like but the cell body possesses a band-form blue-green chromato- 

 phore. In Trichosphoerium, finally, there is no definite test but 

 the body is enclosed in a gelatinous mantle with radial rods in the 

 asexual generation and without these in the sexual generation. 



III. KEY TO GENERA OF SARCODINA. 



Pseudopodia with axial filaments — axo podia 



Class 1. ACTINOPODA 



Pseudopodia without axial filaments . Class 2. Rhizopoda 



Class 1. ACTINOPODA, C\\lkins. 



Marine forms; with central capsule 



Sub-class 2. Radiolaria 

 Mainly fresh water; no central capsule 



Sub-class 1. Heliozoa 



Sub-class 1. HELIOZOA, Haeckel. 

 Naked forms; no jelly mantle or skeleton 



Order 1. Aphrothoraca 



