. Bulletin. 1901-13. Agriculture; Agriculture. is EVOLUTION OF CELLULAR STRUCTURES. PARA6AMIC PHASE KARY APSIS double Dumber of chromosomes. The binucleate structures of the feagi may be referred to as the apaylogamie phase. The so-called "sexual generation" may be called the haplogamlc phast in both cases. These new terms might not be necessary if words were used for descriptive pur- poses only, but in the present instance they have general implications too im- portant to he disre- garded. H a p 1 o g a m i c structures are built between synapsis and plasma psis, apaylogamie be- twe
. Bulletin. 1901-13. Agriculture; Agriculture. is EVOLUTION OF CELLULAR STRUCTURES. PARA6AMIC PHASE KARY APSIS double Dumber of chromosomes. The binucleate structures of the feagi may be referred to as the apaylogamie phase. The so-called "sexual generation" may be called the haplogamlc phast in both cases. These new terms might not be necessary if words were used for descriptive pur- poses only, but in the present instance they have general implications too im- portant to he disre- garded. H a p 1 o g a m i c structures are built between synapsis and plasma psis, apaylogamie be- tween plasmapsis and karyapsis, par- agamic between APAYLOGAMIC PHASE. SYNAPSIS ©JHAPUXAMIC PHASE PLASMAPSIS Fn;. l.—Diagram showing the different types of cell structures and their position in the life history of organisms. LOWER GROUPS Kt 7S HIGHER FUNGI Ks 7S karyapsis and synapsis. Between the three, critical points of cyto- logical activity there are three intervals, in which the organism can pause to gain additional size or numbers by vegetative division of cells. The relations between the cell structures and the nuclear processes are illustrated by the accompanying diagram (fig. 1). No organisms have, however, structures built in till the three phases. The relative impor- tance of each phase in the life histories of the <1 i I' f e re n t natural groups can also be illustrated by simple diagrams, asshown in figure2. The relative im- portance of the dif- ferenl phases in the life history of the various groups of organisms can be represented in another way. as 13 -how n on Plate 1. The diagrams on this plate show in addition a network of descend in its simplest form, composed of successive generations linked together at the firsl stage of conjugation. The generation- themselves are seen to be composed of alternating. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of t
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