II. THE TYPES IN DETAIL WITH JHEIR SUBORDINATE 



GROUPS. 



TYPE I. PROTOZOA. 



Unicellular organisms, single or colonial. Reproduction by fis- 

 sion or gemmation, also by conjugation, which may simulate sex-dif- 

 ferentiation. Colonial forms may show a slight degree of polymor- 

 phism with division of labor, thus serving as transition forms between 

 Protozoa and Metazoa. 



Class I. RHIZOPODA No cell- wall ; move by pseudo- 

 podia. 



Order i . Protoplasta Naked, or with shell made of 



chitin, sand-grains, etc., and con- 

 taining a single large opening, out 

 of which the animal extends its 

 pseudopodia. 

 Sub-order i. Protoplasta 



lobosa With thick, generally rounded 



pseudopodia. 



X Amceba, Difflugia. 

 Sub-order 2. Protoplasta 



filosa With fine, thread-like pseudopodia. 



X Euglypha. 



Order 2. Foraminifera Calcareous shell, perforated with 



innumerable fine openings; all 

 marine. x Gloligerina, Rotalia. 



Order 3. Radiolaria Silicious shell, generally lace-like ; 



marine. 



X Thalassicolla, Acanthometra. 

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