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NEW YORK STATE MUSEUM 



ones continuing to or nearly to the center, where they^ become 

 thickened and some of them much involved or twisted, forming a 

 central spongy axis or pseudocolumella, which becomes solidified 

 and projects prominently from the bottom of the calyx; tabulae 

 and dissepiments present, comparatively infrequent. 



This genus resembles Cyathaxonia, Lophophyllum, 

 A X p.h y 1 1 u m and others in having a strong projection from 

 the bottom of the calyx, but internally it differs from all of them. 



24 



Fig. 23 Kiouelasma mammiferum (Hall). A transverse section 

 sbowing the septa and the pseudocolumella 



24 A longitudinal section showing pseudocolumella and tabulae 



25 Kionelasma herzeri (Hall). A longitudinal section show- 



ing the pseudocolumella and subcystose tabulae 



Nicholson and Etheridge, in their Ponograph of the Silurian 

 fossils of the Girvan district, Ayrshire, pi. 5, fig. 2, illustrate the 

 genus Lindstromia, the enlarged sections of which show a 

 close resemblance to the structure of this genus. But the au- 



