FIGURE 23. AULOSPHAERA ELEGANTISSIMA ( AFTER HAECKEr). DETAIL OF 

 STRUCTURE. 



FIGURE 24. AULOCEROS ( AFTER HAECKER ) . DETAIL SECTION OF SPIKE 



a., lumen of shaft ak., axial canal, h., vesicular enlargement of 

 axial canal at forking of spine, k., secondary silicification. m, 

 membrane. . ' ' 



377 



