General principles of zoology . hange of a part of the cells themselves. In the case of the many-layered epithelia the cells ofthe various layers always can be distinguished by theirform : the deepest layer of cells consists of cylindrical cells;the superficial, on the other hand, of more or less flattenedelements; between lie several layers of transitional forms,so that starting from the cylindrical cells we gradually passthrough the cubical cells to the flat cells of the this arrangement shows, there exists a genetic connec-tion between the cell-layers: the lower cylindrical cells
General principles of zoology . hange of a part of the cells themselves. In the case of the many-layered epithelia the cells ofthe various layers always can be distinguished by theirform : the deepest layer of cells consists of cylindrical cells;the superficial, on the other hand, of more or less flattenedelements; between lie several layers of transitional forms,so that starting from the cylindrical cells we gradually passthrough the cubical cells to the flat cells of the this arrangement shows, there exists a genetic connec-tion between the cell-layers: the lower cylindrical cells arein a state of active multiplication; their descendants withgradual changes of form push into the superficial layers, GENERAL ANATOMY. 9! here to replace an equal quantity of worn-out cells (). In the course of this change of position, the proto-plasmic bodies may undergo an alteration ; in the reptiles,birds, and mammals (Fig. 256) they became cornified,, first the borders, then the inner part of the cell, S It I.
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectzoology, bookyear1896
