318 



DESCK1PTIVE CATALu-.l I 



posed of large, irregularly roundish cells, with thin or very slightly 

 thickened walls. The cells vary, but average about 150-300 /z 

 in diameter. They fit together so as to leave few or no inter- 

 cellular spaces, and are almost identical in shape in transverse 

 and in longitudinal section. In a large number of cases they 

 contain a dark granular contents (see text-fig. 103,*.), which is 

 highly suggestive of starch-granules closely packed. Large num- 

 bers of starch-grains are recorded by Wieland in the American 

 Cycadella (Wieland, 1906, p. 77) and other species. Larger, 

 clearer, spherical or oval contents, apparently similar to structures 



Text-fig. 102. Colymbetes Edwardsi, ap. nov. Transverse section of a small 

 part of the pith showing gum-canal and the ordinary pith-cells; 

 b., pith-cells ; a., lining cells of gum-canal ; c., blackened mass, contents 

 of gum-canal. No. V. 61127 '. 



described as vacuoles by Wieland, are also present in many of the 

 cells. A large proportion of the cells show contents highly 

 suggestive of protoplasm and nucleus. 



Gtim-canah are very numerous and are freely dispersed 

 among the pith-cells ; each canal is formed by about six rather 

 narrow lining cells (see g. and a. text figs. 102, 103); arid the 



