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PROCEEDINGS OF THE NATIONAL MUSEUM 



over with irregular lamellae with open dimorphic zooecia. The nor- 

 mial aspect is that which shows salient groups of large zooecia sur- 

 rounded by variable zones of small zooecia with facettes; these zones 

 may become very large. 



A longitudinal section taken at the extremity of a large branch 

 shows the tubes expanded and recurved at their extremity, with 

 axial gemmation around a large central ramified tube. The small 

 tubes are grouped in special zones. The walls of the tubes are 

 moniliform in their recurved parts. 



A fragment which exteriorily appeared regularly branched showed 

 in longitudinal section the union of two fragments of different 

 origin. 



Finally, a meridian section in a large irregular zoarium shows an 

 extreme complication occasioned by the midtiplicity of the envelop- 

 ing lamellae. 



