364 



Conjugate 



several parietal cushion-like chloroplasts in each semicell, but the parietal 

 disposition is not constant. In many species the chloroplasts are very variable 

 in character and disposition, numerous intermediate states existing between 



ir 1 



'GQQ; 



Fig. 227. A , Pleurotsenium trochiscum 

 W. & G. S. West. B, PL doliiforme 

 W. & G. S. West. Both x 433. 



B 











Fig. 228. A, Euastmm oblongum (Grev.) Ralfs 

 showing the mucilage secreted from one ex- 

 tremity of the cell, x 405 (after Schroder). 

 B, Sta ura strum cuspida turn Br6b. var. maximum 

 W. & G. S. West, x 360. C, St. subpygmseum 

 W. West, x 468. D and E, Arthrodesmus 

 Incus (Breb.) Hass. var. Ealfsii W. & G. S. 

 West foruia latiuscula, x450. 



the truly axile and truly parietal conditions. This is especially noticeable 

 in certain species of Xanthidium, in Staurastrum grande Bulnh. and St. brasi- 

 liense Nordst. var. Lundellii (vide W. & G. S. W., '04 '11). There is little 



