Fig. 1. Silicified mass of stromatoporoid coral full of straight worm tubes (Gitonia) 
which start at various levels in the coral growth. Onondaga limestone (Lower 
Devonian). 
Fig. 2. A solid colony of Stromatopora consiellata from the Upper Silurian (Coble- 
skill limestone) with its surface pitted by the openings of vertical tubes of the worm 
Gitonia sipho. 
40 ORGANIC DEPENDENCE AND DISEASE 
toonecl and wavy markings in the sand, made by the occu- 
pants of these tubes as they swept the sea bottom with their 
extended bodies. They were eager commensals and in the 
Paleozoic faunas we find them in various associations, espe- 
