48 ORGANIC DEPENDENCE AND DISEASE 



ILLUSTEATIONS OF PLEURODICTYUM AND ITS COMMENSAL 

 WOEM HICETES 



Figs. 22 and 23. Top aud side views of the corallum in its normal size and form. 



The apertures of the worm tube are shown at X. 

 Fig. 24. An etching which has the calcareous substance of the base of the coral 



removed and shows the initial convolutions of the worm tube. 

 Fig. 25. The under side of a corallum with the impression of the gastropod 



Loxonema hamiltoniae to which it was attached. 

 Fig. 26. The form of the entire worm tube drawn from an actual specimen. 

 Fig. 27. A shell of Loxonema ImmUtoniae. 



Fig. 28. Vertical section of a corallum, showing the convoluted worm tube. 

 Fig. 29. Enlarged surface of a Loxonema shell which had been the base of 



attachment for the coral. This specimen bears several serpulid worm tubes 



which were there before the coral began to grow. 

 Fig. 30. Section of the coral, showing tubes of more than one worm. 



