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NEW YORK STATE MUSEUM 



Placophyllum, gen. nov. 



Type: Placopliyllum tahulatum sp. nov. Onondaga limestone. 



Corallum consisting of large masses, composed of loosely 

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

 wliich 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. 



Fig. 41 P 1 a c o p h y 1 1 n m t a b u 1 a t u m 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 of A m p 1 e x u s, 

 but the entirely different manner of growth would separate it 

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



