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NEW YORK STATE MUSEUM 



Placophyllum, gen. nov. 



Type: Placophyllum tabulatum sp. nov. Onondaga limestone. 



Corallum consisting of large masses, composed of loosely 

 aggregated, greatly elongate, cylindric stems, of rigid appearance, 

 which in the type species have a diameter of from 8 to 10 mm; 

 exterior with numerous wrinkles of growth; costae distinct. 



At infrequent intervals there are slender lateral processes, 

 which continue to the adjacent coral and serve the purpose of 

 supports. 



41 



Fig. 41Placophyllum tabulatum sp. nov. A longitudinal 

 section showing the tabulae occupying the whole of the internal cavity 



Internally the cysts are absent, the whole interior being occu- 

 pied by strong, broad tabulae. 



The internal structure closely resembles that ofAmplexus, 

 but the entirely different manner of growth would separate it 

 from that genus. The type species, externally, most closely re- 



