ORGANOGRAPHY. 



fectly regular arrangement, when the contiguous cells are of 

 equal size, we have dodecahedral cells, presenting, when cut 

 transversely, a hexagonal appearance {fg. 5). It is rarely how- 

 ever that we find cells of this regular mathematical form, since, 

 in consequence of the unequal size of the contiguous cells, the 

 polygons which result from their mutual pressure must be more 

 or less irregular, and exhibit a variable number of sides 

 (generally from three to eight) (Jig. 4). 



Secondly, when the nutrition is nearly uniform on all sides of 

 the cell-wall, but not equally so at all points of its surface, we 

 have cells which maintain a somewhat rounded form in the 

 centre, but having rays projecting from them in 

 various directions, by which they acquire a some- 

 what star-like appearance {fig. 6) ; and hence 

 such cells are called stellate. These rays maybe 

 situated in one plane, or project from all sides of 

 the cell. It is rarely the case that such cells 

 have the rays at regular intervals, or all of one 

 length, but various degrees of irregularity occur, 

 which lead to corresponding irregular forms in 

 such stellate cells. 

 Thirdly, when the nutrition occurs chiefly in one direction 

 we have cells which are elongated, either horizontally or ver- 



Fiq. 7. 



Fig. 9. 



Fig. 8. 



Fig. 10. 



Fig. 7. Tabular cells Fig. 8. Cylindrical cells. The small or rounded 



body in the interior of three of them is called a nucleus or cytoblast. 

 '.Fiy. a. Elongated fubiform cells Fig. 10. Fibrilliform cells. 



tically. Among the forms resulting from an extension of the 

 cell in breadth or in a horizontal direction, we need only men- 



