SYNOPSIS 387 



PAGE 



/>. Complexity attained by differentiation of cell-wall or by forma- 

 tion of skeletal structures in the protoplasm. 



1 5 Foraminifera . 



Calcareous shells (cell-walls) of various and complicated 

 form 148 



1 6. Radiolaria. 



Membranous perforated shell (cell-wall) and external 

 silicious skeleton often of great complexity : symbiotic 

 relations with Zooxanthella 152 



17. Diatoms. 



Silicious, two-valved, highly-ornamented shells .... 155 



c. Complexity attained by simple elongation and branching of the 

 cell. 



1 8. Mucor. 



A branching filamentous fungus : necessity for special 

 reproductive organs in such an organism : they may be 

 sporangia producing asexual spores, or equal and similar 

 gametes producing a resting zygote 158 



19. Vaiicheria. 



A branched filamentous alga : clear distinction between 

 the gametes or conjugating bodies and the sexual repro- 

 ductive organs or gonads in which they are produced : 

 gonads differentiated into male (spermary) and female 

 (ovary) : gametes differentiated into male (sperm) and 

 female (ovum) : zygote an oosperm 169 



20. Caulerpa. 



Illustrates maximum differentiation ol a unicellular 

 plant : stem-like, leaf-like, and root-like parts 175 



III. ORGANISMS IN WHICH COMPLEXITY is ATTAINED BY CELL- 

 MULTIPLICATION, ACCOMPANIED BY NO OR BUT LITTLE CELL- 

 DlFFERENTIATION. 



a. Linear aggregates. 



21. Penicillium. 



A multicellular, filamentous, branched fungus : mycelial, 

 submerged, and aerial hyphae : apical growth : abundant 

 production of spores by constriction of aerial hyphse . . 184 



22. Agaricus. 



Complexity attained by interweaving of hyphae in a de- 

 finite form : illustrates maximum complexity of a linear 



a gg re g ate > 



C C 2 



