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 



C3O 

 CQQ 



Fig. 227. ^, Pleurotsenium trochiscum 

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

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





Fig. 228. ^4, Euastrum oblongum (Grev.) Ealfs 

 showing the mucilage secreted from one ex- 

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

 B, StaurastrumcuspidatumBr&b.v&r. maximum 

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

 W. West, x468. D and E, Arthrodesmus 

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

 West forma latimcula, x 450. 



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., '0411). There is little 



