CALAMARIEAE. 



335 



internodes are considerably elongated between the pairs. The leaf-whorl 

 forms a horizontal sheath-plate, which is prolonged outwards into a large 

 number of lanceolate sharply pointed teeth. In contrast to all other 

 known kinds of Calamariae, the fertile whorl does not consist of separate 

 free umbrella-like leaves, but forms a connected circular sheath, in- 

 dependent though inserted on the axis close beneath the sterile whorl, 

 and having its somewhat deeply incised margin composed of wedge- 

 shaped almost truncated lobes. Twelve of these lobes were counted 



FIG. 47. Cingularia typica, Weiss. A sterile and fertile whorls, the latter in the upper part of the figure in radial 

 fracture. B diagrammatic reconstruction of two whorls. C fertile whorl from the upper side ; the clear pits correspond 

 to the spots to which the sporangia were attached beneath. After Weiss (6). 



on a perfect whorl figured by Weiss 1 . Stur's reconstruction, in which 

 the lobes are not united at the base into a] sheath, must be corrected by 

 the above description. Each of the lobes is slightly bipartitely mar- 

 ginate along a furrow which follows the median line, and is also divided by 

 a distinct transverse fold into an anterior and a posterior segment. On the 

 under side of each of the somewhat rectangular areolae, formed by the inter- 

 section of the median furrow and the transverse fold, is a circular attachment- 

 scar, which when the preservation is good is surrounded, as the sun by its rays, 

 with a delicate radial striation. The sporangia, four in number, were at- 

 tached to these scars : they were found so connected in a specimen figured 

 by Weiss 2 , in which they hang vertically downwards from the under side 



Weiss (6), t. 8, f. 5. 



Weiss (6), t. 9, f. i. 



