PLATE XXVI. 



Figures magnified 500 diameters. 



Paob. 



Fig. 1. Xanthidium antilopaeum, typical form, front view, 101 



" 2. " " transverse view of semi-cell, 101 



" 3. '• " Var. polymazum, front view, . 101 



" 4. " " lateral view, . . 101 



•' 5. Xanthidium FAScacDLATUM, Var. hexagonum, . . 101 



" 6. " " lateral view, . . 101 



Figs. 7-9. Xanthidium bisenarium, front, side and end views, . 100 



" 10-12. Xanthidium ACULEATUM, front, side and end views, . 99 



" 13-15. Arthrodesmus Rauii, front, end and side views, . . 103 



' 16-18. Arthrodesmus fragilis, two front and one end view, 103 



" 19-21. Arthrodesmus convergens, two front and one end view, . 103 



" 22,23, " " variety with short aculei, . 103 



