ABSTRACT
The causative agent of the bald-sea-urchin disease has been isolated from lesions of diseased individuals. It is a bacterium that would be resistant to the bactericidal substances naturally produced by the echinoids. The bald-sea-urchin disease is a communicable disease which affects several species of regular echinoids. The disease causes conspicuous body-wall lesions. The causative agent of the bald-sea-urchin disease could be a bacterium insensitive to the antibacterial substances naturally produced by the echinoids. Bacterial cultures from necrotic tissues mostly allowed the isolation of nomore than a single strain of bacteria. This bacterial strain is highly infectious for echinoids, producing typical necrosis within a few days of being applied to experimentally injured individuals. In some cases, however, additional strains (i.e. two to three strains) were isolated, but they did not produce any necrosis when tested on echinoids. The bacterial nature of the bald-sea-urchin disease is demonstrated. Spinochromes were demonstrated in lesions caused by the bald-sea-urchin disease.
