CHAPTER VIII THE FORMS OF TISSUES OR CELL-AGGREGATES ( continued )

another cell-wall (a rule whose strict limitations, and narrow range of application, we have already {377} considered) is responsible for many inaccurate or incomplete representations of the mutual arrangement of aggregated cells.

Three schematic diagrams illustrating cellular packing arrangements, showing clusters of polygonal shapes.

Fig. 160. Segmenting egg of Trochus . (After Robert.) Fig. 161. Two views of segmenting egg of Cynthia partita .

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