J ^5 NEW YORK STATE MUSEUM 



PLATE 3 



A series of drawings to illustrate the commensalism of Pleuro- 

 dictyum and the worm Hicetes innexus 

 T , 2 Top and side views of a corallum of Pleurodictyum 

 styloporum Eaton from the Hamilton shales of New 

 York. The worm tubes are clearly seen at x-x on the sur- 

 face of the colony. 



3 Vertical section of a corallum showing sections of the con- 



voluted tube near its base 



4 The under side of a corallum with impression of the gastropod 



Loxonema hamiltoniae to which it is attached 



5 An etching which has removed the base of the coral and shows 



the initial convolutions of the worm tube 



6 The form of the entire tube, drawn from an actual specimen 



7 The basal surface of Pleurodictyum problem- 



atic u m attached to the brachiopod Chonetes 

 sarcinulatus Goldfuss. This specimen is from the 

 Coblentzian at Stadtfeld. 



8 An etching of the basal part of P. styloporum showing 



the chief worm and a wormlike extension which appears to 

 arise from the base of a polypite and turn into an upward 

 course between the cells 



