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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, 

 Axophyllum 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 

 showing the septa and the pseudocolumella 



24 A longitudinal section showing pseudocolumella and tabulae 



25 K 1 o n e 1 a s m a h e r z e r.i {Hall). A longitudinal section show- 



ing the pseudocolumella and subcystose tabulae 



Nicholson and Etheridge, in their Monograph of tlie Silurian 

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

 genus L i n d s t r o m i a, the enlarged sections of which show a 

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



